Exposing physical topology network locality for common workloads

Abstract

In this specification, a technique is discussed that utilizes hierarchical locality information of host machines included in a cluster network for executing a general workload. Hierarchical locality information of each host machine of a plurality of host machines is stored. For each locality of the plurality of localities, the hierarchical locality information of the host machines identifies location information of the locality. In response to receiving a request for executing a workload, the hierarchical locality information of the plurality of host machines is obtained and provided on request (e.g., to a customer).

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 298,683, filed January 12, 2022, and U.S. Nonprovisional Application No. 17 / 935,711, filed September 27, 2022. The entire contents of the foregoing applications are hereby incorporated by reference in their entirety for all purposes.

[0002] Field The present disclosure relates to executing workloads utilizing locality information of host machines included in a cloud infrastructure. [Background technology]

[0003] background Organizations continue to migrate their business applications and databases to the cloud to reduce the costs of purchasing, updating, and maintaining on-premise hardware and software. High performance computing applications consistently consume all available computing power to achieve a specific outcome or result. Such applications require dedicated network performance, fast storage, high computing power, and large amounts of memory - resources that are in short supply in the virtualized infrastructure that makes up today's commodity clouds.

[0004] Cloud infrastructure service providers are offering newer and faster Graphics Processing Units (GPUs) to address the requirements of these applications. GPU workloads are typically executed on one or more host machines. Such workloads typically fail to achieve the expected level of throughput. One of the contributing factors to this problem is the lack of flow entropy (e.g., Equal Cost Multipath (ECMP) flow entropy). The problem is further exacerbated by the fact that host machines (i.e., hosts) exchange traffic without considering other hosts in their local network neighborhood. Other types of workloads are typically executed by selecting one or more host machines from the infrastructure in a random (i.e., arbitrary) manner. That is, the workloads are executed without considering locality information (e.g., the physical location of the host machines). As a result, these workloads have low throughput. The embodiments described herein address these and other problems. Summary of the Invention

[0005] overview The present disclosure generally relates to executing workloads utilizing locality information of host machines included in a cloud infrastructure. Various embodiments are described herein, including methods, systems, non-transitory computer-readable media storing programs, codes, or instructions executable by one or more processors, and the like. These exemplary embodiments are mentioned to provide examples to aid in understanding, not to limit or define the disclosure. Additional embodiments are described in the detailed description section and are described in more detail therein.

[0006] One embodiment of the present disclosure relates to a method that includes storing, for each host machine of a plurality of host machines, hierarchical locality information of the host machine, where the hierarchical locality information of the host machine identifies location information of the host machine for each of a plurality of hierarchical levels; and, in response to receiving a request to execute a workload, obtaining the hierarchical locality information of the plurality of host machines and providing the hierarchical locality information of the plurality of host machines as a response to the request.

[0007] One aspect of the present disclosure provides a system including one or more data processors and a non-transitory computer-readable storage medium including instructions that, when executed on the one or more data processors, cause the one or more data processors to perform some or all of one or more methods disclosed herein.

[0008] Another aspect of the present disclosure provides a computer program product tangibly embodied in a non-transitory machine-readable storage medium that includes instructions configured to cause one or more data processors to perform some or all of one or more of the methods disclosed herein.

[0009] The foregoing, as well as other features and embodiments, will become more apparent with reference to the following specification, claims, and accompanying drawings.

[0010] The features, embodiments, and advantages of the present disclosure will be better understood by reading the following detailed description in conjunction with the accompanying drawings. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a high-level diagram of a distributed environment illustrating a virtual or overlay cloud network hosted by a cloud service provider infrastructure in accordance with certain embodiments. [Diagram 2] FIG. 2 illustrates a simplified architectural diagram of physical components in a physical network within a CSPI in accordance with certain embodiments. [Diagram 3] FIG. 1 illustrates an example deployment in CSPI where a host machine is connected to multiple network virtualization devices (NVDs), according to certain embodiments. [Figure 4] A diagram illustrating connections between host machines and NVDs to provide I / O virtualization to support multi-tenancy in accordance with certain embodiments. [Diagram 5] FIG. 2 illustrates a simplified block diagram of a physical network provided by CSPI in accordance with certain embodiments. [Figure 6] FIG. 1 illustrates a simplified block diagram of a cloud infrastructure incorporating a CLOS network deployment, according to certain embodiments. [Figure 7] FIG. 2 illustrates an exemplary configuration of racks included in a cloud infrastructure, according to certain embodiments. [Figure 8] FIG. 2 is a schematic diagram illustrating a hierarchy of locality information according to certain embodiments. [Figure 9] FIG. 2 illustrates an example tree diagram showing different levels of locality information, in accordance with certain embodiments. [Figure 10] FIG. 2 illustrates an exemplary encoded array of host machine locality information, according to certain embodiments. [Figure 11A] FIG. 2 illustrates an exemplary flowchart illustrating steps performed in provisioning a request, according to certain embodiments. [Figure 11B] FIG. 1 illustrates another exemplary flowchart illustrating steps performed in provisioning a customer's workload request, in accordance with certain embodiments. [Figure 12] FIG. 1 is a block diagram illustrating one pattern for implementing a cloud infrastructure as a service system, according to at least one embodiment. [Figure 13] FIG. 1 is a block diagram illustrating another pattern for implementing a cloud infrastructure as a service system, according to at least one embodiment. [Figure 14]FIG. 1 is a block diagram illustrating another pattern for implementing a cloud infrastructure as a service system, according to at least one embodiment. [Figure 15] FIG. 1 is a block diagram illustrating another pattern for implementing a cloud infrastructure as a service system, according to at least one embodiment. [Figure 16] FIG. 1 is a block diagram illustrating an example computer system in accordance with at least one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Detailed Description In the following description, for purposes of explanation, specific details are set forth in order to provide a thorough understanding of particular embodiments. However, it will be apparent that various embodiments may be practiced without these specific details. The figures and descriptions are not restrictive. As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs.

[0013] Cloud Infrastructure Architecture Examples The term cloud services is generally used to refer to services provided on-demand (e.g., via a subscription model) by a cloud service provider (CSP) to a user or customer using systems and infrastructure (cloud infrastructure) provided by the CSP. Typically, the servers and systems that make up the CSP's infrastructure are separate from the customer's own on-premise servers and systems. Thus, customers can use the cloud services provided by the CSP without having to purchase separate hardware and software resources for the services. Cloud services are designed to provide subscribing customers with easy and scalable access to applications and computing resources without the customer having to invest in procuring the infrastructure used to provide the services.

[0014] There are multiple cloud service providers offering different types of cloud services, which come in a variety of types and models, including Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS), and Infrastructure-as-a-Service (IaaS).

[0015] A customer can subscribe to one or more cloud services offered by a CSP. A customer can be any entity, such as an individual, an organization, or a business. When a customer subscribes or registers for a service offered by a CSP, a tenant or account is created for that customer. Through this account, the customer can then access one or more subscribed cloud resources associated with the account.

[0016] As mentioned earlier, infrastructure as a service (IaaS) is a specific type of cloud computing service. In the IaaS model, the CSP provides infrastructure (called cloud service provider infrastructure or CSPI) that customers can use to build their own customizable network and deploy customer resources. Thus, the customer's resources and network are hosted in a distributed environment by the infrastructure provided by the CSP. This differs from traditional computing, where the customer's resources and network are hosted by the customer-provided infrastructure.

[0017] CSPI may include interconnected high performance computing resources including various host machines, memory resources, and network resources that form a physical network, also called a substrate network or underlay network. CSPI resources may be distributed across one or more data centers, which may be geographically distributed across one or more geographic regions. Virtualization software may provide a distributed environment that is run by and virtualized by these physical resources. Virtualization creates an overlay network (also known as a software-based network, software-defined network, or virtual network) on the physical network. The CSPI physical network provides the foundation for creating one or more overlay or virtual networks on the physical network. The virtual or overlay network may include one or more virtual cloud networks (VCNs). The virtual network is implemented using software virtualization technologies (e.g., hypervisors, functions performed by network virtualization devices (NVDs) (e.g., smart NICs), top-of-rack (TOR) switches, smart TORs that implement one or more functions performed by NVDs, and other mechanisms) to create a layer of network abstraction that can run on the physical network. Virtual networks can take many forms, including peer-to-peer networks, IP networks, etc. Virtual networks are typically either layer 3 IP networks or layer 2 VLANs. This method of virtual or overlay networking is often referred to as a virtual or overlay layer 3 network.Examples of protocols being developed for virtual networks include IP-in-IP (or Generic Routing Encapsulation (GRE)), Virtual Extensible LAN (VXLAN - IETF RFC7348), Virtual Private Networks (VPN) (e.g., MPLS Layer-3 Virtual Private Networks (RFC4364)), VMware's NSX, and Generic Network Virtualization Encapsulation (GENEVE).

[0018] In the case of IaaS, the infrastructure (CSPI) provided by the CSP can be configured to provide computing resources that are virtualized over a public network (e.g., the Internet). In the IaaS model, the cloud computing service provider can host the infrastructure components (e.g., servers, storage devices, network nodes (e.g., hardware), deployment software, platform virtualization (e.g., hypervisor layer), etc.). In some cases, the IaaS provider may also provide various services (e.g., billing, monitoring, logging, security, load balancing, clustering, etc.) that accompany these infrastructure components. Thus, these services may be policy-driven, so that IaaS users may be able to implement policies that drive load balancing to maintain application availability and performance. CSPI provides a set of infrastructure and complementary cloud services that enable customers to build and run a wide range of applications and services in a highly available, hosted, distributed environment. CSPI provides high-performance computing resources and capabilities, as well as storage capacity, in a flexible virtual network that can be securely accessed from various network locations, such as the customer's on-premise network. When a customer subscribes or signs up for an IaaS service offered by a CSP, the tenant created for that customer is a secure, isolated partition within the CSP where the customer can create, organize and manage their cloud resources.

[0019] Customers can build their own virtual networks using compute, memory, and network resources provided by CSPI. These virtual networks can then be deployed with one or more customer resources or workloads, such as compute instances. For example, customers can build one or more customizable private virtual networks, called Virtual Cloud Networks (VCNs), using resources provided by CSPI. Customers can deploy one or more customer resources, such as compute instances, into the customer VCN. Compute instances can take the form of virtual machines, bare metal instances, and so on. Thus, CSPI provides a set of infrastructure and complementary cloud services that enable customers to build and run a wide range of applications and services in a highly available, virtual hosted environment. Customers do not manage or control the underlying physical resources provided by CSPI, but they do have control over the operating systems, storage, and applications deployed, and may also have limited control over selected network components (e.g., firewalls).

[0020] The CSP may provide a console that allows customers and network administrators to configure, access, and manage resources deployed in the cloud using CSPI resources. In certain embodiments, the console provides a web-based user interface that can be used to access and manage the CSPI. In some implementations, the console is a web-based application provided by the CSP.

[0021] CSPI can support single-tenant or multi-tenant architectures. In a single-tenant architecture, software (e.g., applications, databases) or hardware components (e.g., host machines, servers) serve a single customer or tenant. In a multi-tenant architecture, software or hardware components serve multiple customers or tenants. Thus, in a multi-tenant architecture, CSPI resources are shared among multiple customers or tenants. In a multi-tenant situation, precautions are taken and safeguards are implemented within the CSPI to ensure that each tenant's data is isolated and not visible to other tenants.

[0022] In a physical network, a network endpoint ("endpoint") refers to a computing device or system that is connected to the physical network and communicates to and from the connected network. Network endpoints in a physical network may be connected to a local area network (LAN), a wide area network (WAN), or other types of physical networks. Examples of traditional endpoints in a physical network include modems, hubs, bridges, switches, routers, other network devices, physical computers (or host machines), and the like. Each physical device in a physical network has a fixed network address that can be used to communicate with the device. This fixed network address can be a layer 2 address (e.g., a MAC address), a fixed layer 3 address (e.g., an IP address), and the like. In a virtualized environment or virtual network, endpoints can include various virtual endpoints, such as virtual machines hosted by components of the physical network (e.g., hosted by a physical host machine). These endpoints in the virtual network are addressed by overlay addresses, such as overlay layer 2 addresses (e.g., an overlay MAC address) and overlay layer 3 addresses (e.g., an overlay IP address). Network overlays achieve flexibility by allowing network administrators to move overlay addresses associated with network endpoints using software management (e.g., via software that implements the virtual network's control plane). Thus, unlike physical networks, in a virtual network, overlay addresses (e.g., overlay IP addresses) can be moved from one endpoint to another using network management software. Because virtual networks are built on top of physical networks, communication between components in a virtual network involves both the virtual network and the underlying physical network.To facilitate such communications, CSPI components are configured to learn and store mappings that map overlay addresses in the virtual network to actual physical addresses in the substrate network, and vice versa. These mappings are then used to facilitate communications. Customer traffic is encapsulated to facilitate routing in the virtual network.

[0023] Thus, a physical address (e.g., a physical IP address) is associated with an entity in a physical network, and an overlay address (e.g., an overlay IP address) is associated with an entity in a virtual network. Both physical and overlay IP addresses are varieties of real IP addresses. They differ from virtual IP addresses, in which a virtual IP address is mapped to multiple real IP addresses. A virtual IP address provides a one-to-many mapping between a virtual IP address and multiple real IP addresses.

[0024] A cloud infrastructure or CSPI is physically hosted in one or more data centers in one or more regions around the world. The CSPI may include components in a physical or substrate network and virtualized components (e.g., virtual networks, compute instances, virtual machines) in a virtual network built on the physical network components. In certain embodiments, the CSPI is organized and hosted in realms, regions, and availability domains. A region is a localized geographic area that typically includes one or more data centers. Regions are generally independent of each other and may be separated by great distances, for example across countries or continents. For example, a first region may be in Australia, another in Japan, yet another in India, and so on. CSPI resources are divided among regions, so that each region has its own independent subset of CSPI resources. Each region may provide a set of core infrastructure services and resources, such as computing resources (e.g., bare metal servers, virtual machines, containers, and related infrastructure), storage resources (e.g., block volume storage, file storage, object storage, archive storage), network resources (e.g., virtual cloud networks (VCNs), load balancing resources, connections to on-premises networks), database resources, edge network resources (e.g., DNS), and access management and monitoring resources. Typically, each region has multiple paths that connect it to other regions in the realm.

[0025] Typically, applications are deployed in the region where they are most heavily used (i.e., on the infrastructure associated with that region) because using nearby resources is faster than using resources farther away. Applications may also be deployed to different regions for a variety of reasons, such as redundancy to reduce the risk of region-wide events such as large weather systems or earthquakes, or to meet different requirements such as legal jurisdictions, taxation domains, or other business or social criteria.

[0026] Data centers within a region can be further organized and subdivided into availability domains (ADs). An availability domain may correspond to one or more data centers located within a region. A region can consist of one or more availability domains. In such a distributed environment, CSPI resources can be region-specific, such as a virtual cloud network (VCN), or availability domain-specific, such as a compute instance.

[0027] ADs within a region are isolated from each other, fault-tolerant, and configured to be highly unlikely to fail simultaneously. This is achieved by ADs not sharing critical infrastructure resources such as networks, physical cables, cable paths, or cable entry points, so that a failure in one AD in a region is unlikely to affect the availability of other ADs in the same region. ADs within the same region can be connected to each other with low-latency, high-bandwidth networks, providing highly available connections to other networks (e.g., the Internet, customer on-premises networks, etc.) and allowing the creation of systems that are replicated across multiple ADs for both high availability and disaster recovery. Cloud services use multiple ADs to ensure high availability and to protect against resource failures. As the infrastructure offered by an IaaS provider grows, more regions and ADs may be added, along with additional capacity. Traffic between availability domains is typically encrypted.

[0028] In certain embodiments, regions are grouped into realms. A realm is a logical collection of regions. Realms are isolated from each other and do not share data. Regions in the same realm can communicate with each other, but regions in different realms cannot. A customer's tenant or account at a CSP exists in a single realm and can be spread across one or more regions that belong to that realm. Typically, when a customer subscribes to an IaaS service, the customer's tenant or account is created in a customer-specified region (called the "home" region) within the realm. The customer can extend the customer's tenant across one or more other regions within the realm. The customer cannot access regions outside the realm in which the customer's tenant resides.

[0029] An IaaS provider may offer multiple realms, with each realm corresponding to a particular set of customers or users. For example, a commercial realm may be offered for commercial customers. As another example, a realm specific to that country may be offered for customers within a particular country. As yet another example, a government realm may be offered for governments, etc. For example, the government realm may be created for a particular government and may have a higher level of security than the commercial realm. For example, Oracle Cloud Infrastructure (OCI) currently offers a realm for commercial regions and two realms for government cloud regions (e.g., FedRAMP certified and IL5 certified).

[0030] In certain embodiments, an AD can be divided into one or more failure domains. A failure domain is a grouping of infrastructure resources within an AD to provide anti-affinity. Fault domains allow computing instances to be distributed so that instances are not on the same physical hardware within a single AD. This is known as anti-affinity. A failure domain refers to a set of hardware components (e.g., computers, switches) that share a single point of failure. A computing pool is logically divided into failure domains. Thus, a hardware failure or a computing hardware maintenance event that affects one failure domain does not affect instances in other failure domains. Depending on the embodiment, the number of failure domains in each AD may vary. For example, in certain embodiments, each AD includes three failure domains. Fault domains act as logical data centers within an AD.

[0031] When a customer subscribes to an IaaS service, resources from CSPI are provisioned for the customer and associated with the customer's tenant. The customer can use these provisioned resources to build private networks and deploy resources on these networks. A customer network hosted in the cloud by CSPI is called a Virtual Cloud Network (VCN). A customer can set up one or more Virtual Cloud Networks (VCNs) using CSPI resources allocated to the customer. A VCN is a virtual or software-defined private network. The customer resources deployed in the customer's VCN may include computing instances (e.g., virtual machines, bare metal instances) and other resources. These computing instances may represent various customer workloads such as applications, load balancers, databases, etc. Computing instances deployed in a VCN can communicate with endpoints publicly accessible over a public network such as the Internet ("public endpoints"), other instances in the same VCN or other VCNs (e.g., other VCNs of the customer, VCNs not belonging to the customer), the customer's on-premise data center or network, service endpoints, and other types of endpoints.

[0032] CSPs can use CSPI to provide various services. In some cases, CSPI customers themselves can act as service providers and provide services using CSPI resources. Service providers may expose service endpoints characterized by identifying information (e.g., IP addresses, DNS names, ports). Customer resources (e.g., computing instances) can consume a particular service by accessing the service endpoints exposed by the service for that particular service. These service endpoints are typically endpoints that are publicly accessible by users using a public IP address associated with the endpoint over a public communications network such as the Internet. Publicly accessible network endpoints are sometimes referred to as public endpoints.

[0033] In certain embodiments, a service provider may expose a service through a service endpoint (sometimes referred to as a service endpoint). Customers of the service may then use the service endpoint to access the service. In certain implementations, a service endpoint provided for a service may be accessible by multiple customers wishing to utilize the service. In other implementations, a dedicated service endpoint may be provided for a customer such that only that customer may access the service using the dedicated service endpoint.

[0034] In certain embodiments, when a VCN is created, it is associated with a private overlay Classless Inter-Domain Routing (CIDR) address space, which is a range of private overlay IP addresses (e.g., 10.0 / 16) that are assigned to the VCN. A VCN includes associated subnets, route tables, and gateways. A VCN exists within a single region but can span one or more or all of the region's availability domains. A gateway is a virtual interface configured for a VCN that allows traffic to communicate between the VCN and one or more endpoints outside the VCN. One or more different types of gateways can be configured for a VCN to allow communication with different types of endpoints.

[0035] A VCN can be divided into one or more subnetworks, such as one or more subnets. A subnet is thus a unit of organization or subdivision that can be created within a VCN. A VCN can contain one or more subnets. Each subnet in a VCN is associated with a contiguous range of overlay IP addresses that do not overlap with other subnets in that VCN and that represent a subset of address space within the VCN's address space (for example, 10.0.0.0 / 24 and 10.0.1.0 / 24).

[0036] Each compute instance is associated with a virtual network interface card (VNIC) that allows the compute instance to participate in a subnet in a VCN. A VNIC is a logical representation of a physical network interface card (NIC). In general, a VNIC is an interface between an entity (e.g., compute instance, service) and a virtual network. A VNIC exists within a subnet and has one or more associated IP addresses and associated security rules or policies. A VNIC is equivalent to a layer 2 port on a switch. A VNIC connects a compute instance to a subnet in a VCN. A VNIC associated with a compute instance allows the compute instance to be part of a subnet in a VCN, allowing the compute instance to communicate (e.g., send and receive packets) with endpoints on the same subnet as the compute instance, endpoints in a different subnet in the VCN, or endpoints outside the VCN. Thus, the VNIC associated with a compute instance determines how the compute instance connects to endpoints inside and outside the VCN. When a compute instance is created and added to a subnet in a VCN, a VNIC is created for the compute instance and associated with that compute instance. For a subnet consisting of a set of compute instances, the subnet contains VNICs corresponding to the set of compute instances, and each VNIC connects to a compute instance in the set of compute instances.

[0037] Each compute instance is assigned a private overlay IP address through the VNIC associated with the compute instance. This private overlay IP address is assigned to the VNIC associated with the compute instance when the compute instance is created and is used to route traffic to and from the compute instance. All VNICs within a particular subnet use the same route table, security lists, and DHCP options. As previously mentioned, each subnet in a VCN is associated with a contiguous range of overlay IP addresses (e.g., 10.0.0.0 / 24 and 10.0.1.0 / 24) that do not overlap with other subnets in that VCN and that represent a subset of address space within the VCN's address space. For a VNIC on a particular subnet of a VCN, the private overlay IP address assigned to the VNIC is an address from the contiguous range of overlay IP addresses assigned to the subnet.

[0038] In certain embodiments, a compute instance may be optionally assigned additional overlay IP addresses, such as one or more public IP addresses if in a public subnet, in addition to the private overlay IP address. These multiple addresses are assigned on the same VNIC or on multiple VNICs associated with the compute instance. However, each instance has a primary VNIC associated with an overlay private IP address that is created and assigned to the instance when the instance is launched, and this primary VNIC cannot be deleted. Additional VNICs, called secondary VNICs, can be added to an existing instance in the same availability domain as the primary VNIC. All VNICs are in the same availability domain as the instance. The secondary VNICs can be in a subnet in the same VCN as the primary VNIC, or in a different subnet in the same VCN or in a different VCN.

[0039] If a compute instance is in a public subnet, it can optionally be assigned a public IP address. A subnet can be designated as either a public or private subnet when it is created. A private subnet means that resources in the subnet (e.g., compute instances) and associated VNICs cannot have public overlay IP addresses. A public subnet means that resources in the subnet and associated VNICs can have public IP addresses. Customers can specify that a subnet be in a single availability domain or across multiple availability domains within a region or realm.

[0040] As mentioned above, a VCN may be divided into one or more subnets. In certain embodiments, a virtual router (VR) (referred to as a VCN VR or simply VR) configured for a VCN allows communication between subnets of the VCN. For a subnet in a VCN, the VR represents a logical gateway for that subnet, allowing the subnet (i.e., the compute instances on that subnet) to communicate with endpoints on other subnets in the VCN and other endpoints outside the VCN. A VCN VR is a logical entity configured to route traffic between VNICs in a VCN and a virtual gateway ("gateway") associated with the VCN. Gateways are described in more detail below with reference to FIG. 1. A VCN VR is a layer 3 / IP layer concept. In one embodiment, there is one VCN VR for a VCN, and a VCN VR may have an unlimited number of ports that are addressed by IP addresses, one port for each subnet of the VCN. Thus, a VCN VR has a different IP address for each subnet in the VCN to which the VCN VR is connected. The VRs are also connected to various gateways configured for the VCN. In certain embodiments, a particular overlay IP address from a subnet's overlay IP address range is reserved for a port in the VCN VR of that subnet. For example, consider a VCN with two subnets, each with an associated address range of 10.0 / 16 and 10.1 / 16. For a first subnet in the VCN with an address range of 10.0 / 16, an address in this range is reserved for a port in the VCN VR of that subnet. In some cases, the first IP address in the range may be reserved for a VCN VR. For example, for a subnet with an overlay IP address range of 10.0 / 16, an IP address of 10.0.0.1 may be reserved for a port in the VCN VR of that subnet. For a second subnet in the same VCN with an address range of 10.1 / 16, the VCN VR may have a port for that second subnet with an IP address of 10.1.0.1. The VCN VR has a different IP address for each subnet in the VCN.

[0041] In some other embodiments, each subnet in a VCN may have its own associated VR that is addressable by the subnet using a reserved or default IP address associated with the VR. The reserved or default IP address may be, for example, the first IP address of a range of IP addresses associated with the subnet. VNICs in the subnet can use this default or reserved IP address to communicate (e.g., send and receive packets) with the VR associated with the subnet. In such embodiments, the VR becomes an ingress / egress point for the subnet. VRs associated with a subnet in a VCN can communicate with other VRs associated with other subnets in the VCN. The VRs can also communicate with gateways associated with the VCN. The VR functions for a subnet are run on or performed by one or more NVDs that perform VNIC functions for the VNICs in the subnet.

[0042] You can configure route tables, security rules, and DHCP options for a VCN. A route table is a virtual route table for a VCN that contains rules to route traffic from subnets in the VCN to destinations outside the VCN through a gateway or a specially configured instance. You can customize a VCN's route table to control how packets are forwarded and routed into and out of the VCN. DHCP options refer to configuration information that is automatically provided when an instance is launched.

[0043] Security rules configured for a VCN represent the overlay firewall rules for the VCN. Security rules can include ingress and egress rules and can specify the type of traffic (e.g., based on protocol and port) that can enter and exit instances in the VCN. Customers can choose whether a particular rule is stateful or stateless. For example, a customer can allow SSH traffic to come from anywhere to a set of instances by configuring a stateful ingress rule with source CIDR 0.0.0.0 / 0, destination TCP port 22. Security rules can be implemented using network security groups or security lists. A network security group consists of a set of security rules that apply only to resources in that group. On the other hand, a security list contains rules that apply to all resources in a subnet that uses the security list. A VCN can be provided with a default security list that contains default security rules. DHCP options configured for a VCN provide configuration information that is automatically provided to instances in the VCN when the instances are launched.

[0044] In certain embodiments, configuration information for a VCN is determined and stored by a VCN control plane. The configuration information for a VCN may include, for example, information about address ranges associated with the VCN, subnets and related information within the VCN, one or more VRs associated with the VCN, computing instances and related VNICs within the VCN, NVDs performing various virtualized network functions (e.g., VNICs, VRs, gateways) associated with the VCN, state information for the VCN, and other VCN-related information. In certain embodiments, the VCN distribution service publishes the configuration information stored by the VCN control plane, or a portion thereof, to the NVD. The distributed information may be stored by the NVD and used to update information (e.g., forwarding tables, routing tables) used to forward packets to and from computing instances in the VCN.

[0045] In certain embodiments, the creation of VCNs and subnets is handled by a VCN control plane (CP), and the launch of compute instances is handled by a compute control plane. The compute control plane is responsible for allocating physical resources for compute instances and then calls the VCN control plane to create and attach VNICs to compute instances. The VCN CP also sends VCN data mappings to the VCN data plane, which is configured to perform packet forwarding and routing functions. In certain embodiments, the VCN CP provides a distribution service that is responsible for providing updates to the VCN data plane. Examples of the VCN control plane are also shown in Figures 12, 13, 14, and 15 (see references 1216, 1316, 1416, and 1516) and described below.

[0046] A customer may create one or more VCNs using resources hosted by CSPI. Computing instances deployed in a customer's VCN may communicate with various endpoints. These endpoints may include endpoints hosted by CSPI and endpoints external to CSPI.

[0047] A variety of different architectures for implementing cloud-based services using CSPI are illustrated in Figures 1, 2, 3, 4, 5, 12, 13, 14, and 15 and described below. Figure 1 is a high-level diagram of a distributed environment 100 illustrating an overlay or customer VCN hosted by CSPI according to certain embodiments. The distributed environment illustrated in Figure 1 includes multiple components in an overlay network. The distributed environment 100 illustrated in Figure 1 is merely an example and is not intended to unduly limit the scope of the claimed embodiments. Many variations, alternatives, and modifications are possible. For example, in some implementations, the distributed environment illustrated in Figure 1 may include more or fewer systems or components than those illustrated in Figure 1, may combine two or more systems, or may have a different configuration or arrangement of systems.

[0048] As shown in the example depicted in FIG. 1, distributed environment 100 includes CSPI 101, which provides services and resources that customers can subscribe to and use to build a virtual cloud network (VCN). In a particular embodiment, CSPI 101 provides IaaS services to subscribing customers. Data centers in CSPI 101 may be organized into one or more regions. An example region, “RegionUS” 102, is shown in FIG. 1. A customer has configured a customer VCN 104 in region 102. A customer may deploy various computing instances on VCN 104. The computing instances may include virtual machines or bare metal instances. Example instances include applications, databases, load balancers, etc.

[0049] In the embodiment shown in FIG. 1, customer VCN 104 is composed of two subnets, "Subnet 1" and "Subnet 2," each with its own CIDR IP address range. In FIG. 1, Subnet 1 has an overlay IP address range of 10.0 / 16, and Subnet 2 has an address range of 10.1 / 16. VCN virtual router 105 represents a logical gateway for the VCN that enables communication between subnets in VCN 104 and with other endpoints outside the VCN. VCN VR 105 is configured to route traffic between VNICs in VCN 104 and gateways associated with VCN 104. VCN VR 105 provides ports to each subnet in VCN 104. For example, VR 105 can provide a port with IP address 10.0.0.1 to Subnet 1 and a port with IP address 10.1.0.1 to Subnet 2.

[0050] Multiple computing instances may be deployed in each subnet, and the computing instances may be virtual machine instances and / or bare metal instances. The computing instances in a subnet may be hosted by one or more host machines in CSPI101. The computing instances join the subnet through the VNIC associated with the computing instance. For example, as shown in FIG. 1, computing instance C1 becomes part of subnet 1 through the VNIC associated with the computing instance. Similarly, computing instance C2 becomes part of subnet 1 through the VNIC associated with C2. Similarly, multiple computing instances, which may be virtual machine instances or bare metal instances, may be part of subnet 1. Each computing instance is assigned a private overlay IP address and a MAC address through the associated VNIC. For example, in FIG. 1, computing instance C1 has an overlay IP address of 10.0.0.2 and a MAC address of M1, while computing instance C2 has a private overlay IP address of 10.0.0.3 and a MAC address of M2. Each computing instance in subnet 1, including computing instances C1 and C2, has a default route to VCN VR105 using IP address 10.0.0.1. This is the IP address of a port in VCN VR105 in Subnet 1.

[0051] Multiple computing instances, such as virtual machine instances and / or bare metal instances, may be deployed in Subnet 2. For example, as shown in FIG. 1, computing instances D1 and D2 become part of Subnet 2 through the VNICs associated with the respective computing instances. In the embodiment shown in FIG. 1, computing instance D1 has an overlay IP address 10.1.0.2 and a MAC address MM1, and computing instance D2 has a private overlay IP address 10.1.0.3 and a MAC address MM2. Each computing instance in Subnet 2 (including computing instances D1 and D2) has a default route to VCN VR105 using IP address 10.1.0.1, which is the IP address of a port in VCN VR105 in Subnet 2.

[0052] VCN A 104 may also include one or more load balancers. For example, a load balancer may be provided for a subnet and configured to load balance traffic among multiple computing instances on the subnet. A load balancer may be provided to load balance traffic among subnets in the VCN.

[0053] A particular computing instance deployed on VCN 104 can communicate with a variety of different endpoints. These endpoints can include endpoints hosted by CSPI 200 and endpoints external to CSPI 200. Endpoints hosted by CSPI 101 can include endpoints on the same subnet as the particular computing instance (e.g., communication between two computing instances in subnet 1), endpoints on a different subnet but in the same VCN (e.g., communication between a computing instance in subnet 1 and a computing instance in subnet 2), endpoints in different VCNs in the same region (e.g., communication between a computing instance in subnet 1 and an endpoint in a VCN in the same region 106 or 110, communication between a computing instance in subnet 1 and an endpoint in a service network 110 in the same region), or endpoints in a VCN in a different region (e.g., communication between a computing instance in subnet 1 and an endpoint in a VCN in a different region 108). Computing instances in a subnet hosted by CSPI 101 can also communicate with endpoints not hosted by CSPI 101 (i.e., external to CSPI 101). These external endpoints include endpoints within the customer's on-premise network 116, endpoints within other remote cloud host networks 118, public endpoints 114 accessible via public networks such as the Internet, and other endpoints.

[0054] Communication between compute instances on the same subnet is facilitated using VNICs associated with the source and destination compute instances. For example, compute instance C1 in Subnet 1 may want to send a packet to compute instance C2 in Subnet 1. For a packet originating from a source compute instance and destined for another compute instance in the same subnet, the packet is first processed by the VNIC associated with the source compute instance. The processing performed by the VNIC associated with the source compute instance may include determining the packet's destination information from the packet header, identifying policies (e.g., security lists) configured on the VNIC associated with the source compute instance, determining the next hop for the packet, performing encapsulation / decapsulation functions on the packet as necessary, and forwarding / routing the packet to the next hop to facilitate communication of the packet to its intended destination. If the destination compute instance is in the same subnet as the source compute instance, the VNIC associated with the source compute instance is configured to identify the VNIC associated with the destination compute instance and forward the packet to that VNIC for processing. The VNIC associated with the destination compute instance is then exercised to forward the packet to the destination compute instance.

[0055] When a packet is communicated from a compute instance in a subnet to an endpoint in another subnet in the same VCN, the communication is facilitated by the VNICs associated with the source and destination compute instances and VCN VRs. For example, if compute instance C1 in subnet 1 in Figure 1 wants to send a packet to compute instance D1 in subnet 2, the packet is first processed by the VNIC associated with compute instance C1. The VNIC associated with compute instance C1 is configured to route the packet to VCN VR105 using the default route or port 10.0.0.1 in the VCN VR105. VCN VR105 is configured to route the packet to subnet 2 using port 10.1.0.1. The packet is then received and processed by the VNIC associated with D1, which forwards the packet to compute instance D1.

[0056] When a packet is communicated from a compute instance in VCN 104 to an endpoint outside VCN 104, the communication is facilitated by the VNIC associated with the source compute instance, the VCN VR 105, and a gateway associated with VCN 104. VCN 104 may have one or more types of gateways associated with it. A gateway is an interface between a VCN and another endpoint, where the other endpoint is outside of the VCN. A gateway is a layer 3 / IP layer concept that allows a VCN to communicate with endpoints outside of the VCN. Thus, a gateway facilitates traffic flow between a VCN and other VCNs or networks. Different types of gateways can be configured in a VCN to facilitate different types of communication with different types of endpoints. Depending on the gateway, the communication may occur over a public network (e.g., the Internet) or over a private network. Various communication protocols may be used for these communications.

[0057] For example, compute instance C1 may want to communicate with an endpoint outside of VCN 104. The packet may first be processed by a VNIC associated with source compute instance C1. The VNIC processing determines that the destination of the packet is outside of Subnet 1 of C1. The VNIC associated with C1 may forward the packet to VCN VR 105 of VCN 104. VCN VR 105 then processes the packet and as part of the processing determines a particular gateway associated with VCN 104 as the next hop for the packet based on the destination of the packet. VCN VR 105 may then forward the packet to the particular identified gateway. For example, if the destination is an endpoint within a customer's on-premise network, the packet may be forwarded by VCN VR 105 to a dynamic routing gateway (DRG) gateway 122 configured for VCN 104. The packet may then be forwarded from the gateway to the next hop to facilitate communication of the packet to its ultimate intended destination.

[0058] Various types of gateways can be configured for a VCN. Examples of gateways that can be configured for a VCN are shown in FIG. 1 and described below. Examples of gateways associated with a VCN are also shown in FIGS. 12, 13, 14, and 15 (e.g., gateways referenced with reference numbers 1234, 1236, 1238, 1334, 1336, 1338, 1434, 1436, 1438, 1534, 1536, and 1538) and described below. As shown in the embodiment shown in FIG. 1, a dynamic routing gateway (DRG) 122 can be added to or associated with a customer VCN 104 to provide a path for private network traffic communication between the customer VCN 104 and another endpoint. Here, the other endpoint can be a customer's on-premise network 116, a VCN 108 in another region of the CSPI 101, or another remote cloud network 118 not hosted by the CSPI 101. The customer on-premise network 116 may be a customer network or customer data center built using the customer's resources. Access to the customer on-premise network 116 is typically very restricted. For a customer with both a customer on-premise network 116 and one or more VCNs 104 deployed or hosted in the cloud by CSPI 101, the customer may want to enable the on-premise network 116 and the cloud-based VCNs 104 to communicate with each other. This allows the customer to build an extended hybrid environment that includes the customer's VCNs 104 and the on-premise network 116 hosted by CSPI 101. The DRG 122 enables this communication. To enable such communication, a communication channel 124 is set up, with one endpoint of the channel in the customer's on-premise network 116 and another endpoint in CSPI 101, connected to the customer's VCN 104. The communication channel 124 may be over a public or private communication network, such as the Internet.A variety of communication protocols can be used, such as IPsec VPN technology over a public communication network such as the Internet, or Oracle's FastConnect technology, which uses a private network instead of a public network. The device or equipment in the customer on-premise network 116 that forms one endpoint of the communication channel 124 is called customer premises equipment (CPE), such as the CPE 126 shown in FIG. 1. On the CSPI 101 side, the endpoint can be a host machine running the DRG 122. In certain embodiments, remote peering connections (RPCs) can be added to the DRG to allow a customer to peer one VCN with another VCN in another region. Such RPCs allow the customer VCN 104 to connect to a VCN 108 in another region using the DRG 122. The DRG 122 can also be used to communicate with other remote cloud networks 118 not hosted in the CSPI 101, such as Microsoft Azure cloud, Amazon AWS cloud, etc.

[0059] As shown in FIG. 1, an Internet Gateway (IGW) 120 is configured for customer VCN 104 to enable computing instances on VCN 104 to communicate with public endpoints 114 accessible over a public network, such as the Internet. IGW 120 is a gateway that connects a VCN to a public network, such as the Internet. IGW 120 allows public subnets in a VCN, such as VCN 104 (where resources in the public subnet have public overlay IP addresses) to directly access public endpoints 112 on the public network 114, such as the Internet. IGW 120 allows connections to be initiated from subnets in VCN 104 or from the Internet.

[0060] A network address translation (NAT) gateway 128 can be configured for a customer's VCN 104 to enable cloud resources in the customer's VCN that do not have dedicated public overlay IP addresses to access the Internet, and achieves this without exposing these resources to direct incoming Internet connections (e.g., L4-L7 connections). This allows private subnets in the VCN, such as Private Subnet 1 in VCN 104, to privately access public endpoints on the Internet. A NAT gateway only allows connections to be initiated from the private subnet to the public Internet, not from the Internet to the private subnet.

[0061] In certain embodiments, a service gateway (SGW) 126 can be configured for a customer VCN 104 and provides a path for private network traffic between the VCN 104 and supported service endpoints in the service network 110. In certain embodiments, the service network 110 may be provided by a CSP and provide a variety of services. An example of such a service network is Oracle's service network, which provides a variety of services available to customers. For example, a computing instance (e.g., a database system) in a private subnet of the customer VCN 104 can back up data to a service endpoint (e.g., an object store) without requiring a public IP address or access to the Internet. In certain embodiments, a VCN can have only one SGW, and connections can be initiated only from subnets within the VCN, not from the service network 110. When a VCN is peered with another VCN, resources in the other VCN typically do not have access to the SGW. Resources in an on-premises network connected to a VCN using a FastConnect or VPN connection can also use a service gateway configured for that VCN.

[0062] In certain implementations, the SGW 126 uses the concept of a service Classless Inter-Domain Routing (CIDR) label, which is a string that represents the public IP address range of all regions for a given service or group of services. Customers use the service CIDR label when configuring the SGW and associated route rules to control traffic to the service. Customers can optionally leverage this when configuring security rules without having to adjust the security rules if the service's public IP address changes in the future.

[0063] A local peering gateway (LPG) 132 is a gateway that can be added to a customer VCN 104 to allow the VCN 104 to peer with another VCN in the same region. Peering means that the VCNs communicate using private IP addresses without the traffic traversing a public network such as the Internet or routing the traffic through the customer's on-premises network 116. In a preferred embodiment, a VCN has a separate LPG for each peering it establishes. Local peering or VCN peering is a common method used to establish network connectivity between different applications or infrastructure management functions.

[0064] A service provider, such as a provider of services in the service network 110, can provide access to a service using different access models. According to a public access model, the service may be exposed as a public endpoint publicly accessible by computing instances in the customer VCN over a public network such as the Internet, or it may be privately accessible through the SGW 126. According to a particular private access model, the service is made accessible as a private IP endpoint in a private subnet in the customer's VCN. This is called private endpoint (PE) access and allows the service provider to expose the service as an instance in the customer's private network. A private endpoint resource represents a service in the customer's VCN. Each PE appears as a VNIC (called a PE-VNIC with one or more private IPs) in a customer-selected subnet in the customer's VCN. Thus, the PE provides a way to offer a service in a private customer VCN subnet using a VNIC. Because the endpoint is exposed as a VNIC, all the features associated with a VNIC, such as routing rules, security lists, etc., become available on the PE VNIC.

[0065] A service provider can register a service to make it accessible through the PE. The provider can associate a policy with the service that restricts the visibility of the service to a customer tenant. The provider can register multiple services under a single virtual IP address (VIP), especially for multi-tenant services. There can be multiple such private endpoints (in multiple VCNs) that represent the same service.

[0066] Compute instances in the private subnet can then access the service using the private IP address of the PE VNIC or the service DNS name. Compute instances in the customer VCN can access the service by sending traffic to the private IP address of the PE in the customer VCN. A private access gateway (PAGW) 130 is a gateway resource that can be connected to a service provider VCN (e.g., a VCN in the service network 110) and serves as an ingress / egress point for all traffic to and from private endpoints in the customer subnet. Using PAGW 130, a provider can scale the number of PE connections without utilizing internal IP address resources. A provider needs to configure only one PAGW for any number of services registered in a single VCN. A provider can represent services as private endpoints in multiple VCNs for one or more customers. From the customer's perspective, the PE VNIC does not appear to be connected to the customer's instances, but to the services the customer wants to interact with. Traffic destined for the private endpoints is routed to the service through PAGW 130. These are called customer-to-service private connections (C2S connections).

[0067] The PE concept can also be used to extend private access of services to customer on-premise networks and datacenters by allowing traffic to traverse FastConnect / IPsec links and private endpoints in the customer VCN. Private access of services can also be extended to customer peer VCNs by allowing traffic to flow between LPG132 and the PEs in the customer VCN.

[0068] Customers can control routing within a VCN at the subnet level, allowing them to specify which subnets within a customer's VCN, such as VCN 104, use each gateway. A VCN's route table is used to determine whether to allow traffic from a VCN through a particular gateway. For example, in a particular instance, a route table for a public subnet in customer VCN 104 may send non-local traffic through IGW 120. A route table for a private subnet in the same customer VCN 104 may send traffic destined for a CSP service through SGW 126. All remaining traffic may be sent through NAT gateway 128. Route tables only control traffic that leaves a VCN.

[0069] Security lists associated with a VCN are used to control traffic that enters the VCN on inbound connections through the gateway. All resources in a subnet use the same route table and security lists. Security lists can be used to control specific types of traffic that can enter or exit instances in a VCN's subnets. Security list rules can include ingress (inbound) rules and egress (outbound) rules. For example, an ingress rule can specify an allowed source address range, and an egress rule can specify an allowed destination address range. Security rules can specify a specific protocol (e.g., TCP, ICMP), a specific port (e.g., 22 for SSH, 3389 for Windows RDP), and so on. In a specific implementation, the instance's operating system can apply its own firewall rules that comply with the security list rules. Rules can be stateful (e.g., connections are tracked and responses are automatically allowed without an explicit security list rule for the response traffic) or stateless.

[0070] Access from a customer VCN (i.e., by resources or computing instances deployed on VCN 104) can be categorized as public access, private access, or dedicated access. Public access refers to an access model that uses a public IP address or NAT to access a public endpoint. Private access enables customer workloads in VCN 104 with private IP addresses (e.g., resources in a private subnet) to access a service without going through a public network such as the Internet. In certain embodiments, CSPI 101 enables customer VCN workloads with private IP addresses to access (public service endpoints of) a service using a service gateway. Thus, the service gateway provides a private access model by establishing a virtual link between the customer's VCN and the public endpoint of the service that is outside the customer's private network.

[0071] Additionally, CSPI may provide dedicated public access using technologies such as FastConnect public peering. A customer's on-premises instances can use the FastConnect connection to access one or more services in the customer VCN without traversing a public network such as the Internet. CSPI may also provide dedicated private access using FastConnect private peering, allowing a customer's on-premises instances with private IP addresses to access the customer's VCN workloads using the FastConnect connection. FastConnect is a network connectivity alternative to connect a customer's on-premises network to CSPI and its services using the public Internet. FastConnect provides an easy, flexible, and economical way to create dedicated private connections with higher bandwidth options and a more reliable and consistent network experience compared to Internet-based connections.

[0072] FIG. 1 and the accompanying description above describe various virtualized components within an exemplary virtual network. As previously mentioned, a virtual network is built on an underlying physical or substrate network. FIG. 2 illustrates a simplified architectural diagram of physical components within a physical network within CSPI 200 that provides an underlay for a virtual network according to certain embodiments. As shown, CSPI 200 provides a distributed environment comprised of components and resources (e.g., computing, memory, network resources) provided by a cloud service provider (CSP). These components and resources are used to provide cloud services (e.g., IaaS services) to subscribing customers, i.e., customers who subscribe to one or more services provided by the CSP. Based on the services to which the customer subscribes, a subset of the resources (e.g., computing, memory, network resources) of CSPI 200 is provisioned to the customer. The customer can then build their own cloud-based (i.e., CSPI-hosted), customizable, private virtual network using the physical computing, memory, and network resources provided by CSPI 200. As previously mentioned, these customer networks are referred to as Virtual Cloud Networks (VCNs). Customers can deploy one or more customer resources, such as compute instances, into these Customer VCNs. The compute instances can be in the form of virtual machines, bare metal instances, etc. CSPI200 provides a set of infrastructure and complementary cloud services that enable customers to build and run a wide range of applications and services in a highly available hosted environment.

[0073] In the example shown in FIG. 2, the physical components of CSPI 200 include one or more physical host machines or servers (e.g., 202, 206, 208), network virtualization devices (NVDs) (e.g., 210, 212), top-of-rack (TOR) switches (e.g., 214, 216), a physical network (e.g., 218), and switches within physical network 218. The physical host machines or servers can host and execute various computing instances that participate in one or more subnets of the VCN. The computing instances can include virtual machine instances and bare metal instances. For example, the various computing instances shown in FIG. 1 can be hosted by the physical host machines shown in FIG. 2. The virtual machine computing instances in the VCN can be executed by one host machine or multiple different host machines. The physical host machines can also host virtual host machines, container-based hosts or functions, etc. The VNICs and VCN VRs shown in FIG. 1 can be executed by the NVDs shown in FIG. 2. The gateways shown in FIG. 1 can be executed by the host machines and / or NVDs shown in FIG. 2.

[0074] A host machine or server may run a hypervisor (also called a virtual machine monitor or VMM) that creates and enables a virtualized environment on the host machine. Virtualization or a virtualized environment facilitates cloud-based computing. A hypervisor on a host machine may create, run, and manage one or more computing instances on the host machine. A hypervisor on a host machine allows the physical computing resources of the host machine (e.g., computing, memory, network resources) to be shared among the various computing instances executed by the host machine.

[0075] For example, as shown in FIG. 2, host machines 202 and 208 run hypervisors 260 and 266, respectively. These hypervisors can be implemented using software, firmware, hardware, or a combination thereof. Typically, a hypervisor is a process or software layer that sits on top of a host machine's operating system (OS) and then runs on the host machine's hardware processor. A hypervisor provides a virtualized environment by allowing the host machine's physical computing resources (e.g., processing resources such as processors / cores, memory resources, network resources) to be shared among various virtual machine computing instances executed by the host machine. For example, in FIG. 2, hypervisor 260 sits on top of host machine 202's OS and allows host machine 202's computing resources (e.g., processing, memory, and network resources) to be shared among computing instances (e.g., virtual machines) executed by host machine 202. A virtual machine can have its own operating system (called a guest operating system), which may be the same or different from the host machine's OS. The operating system of a virtual machine executed by a host machine may be the same or different from the operating system of another virtual machine executed by the same host machine. Thus, a hypervisor allows multiple operating systems to run alongside each other while sharing the same computing resources of the host machine. The host machines shown in Figure 2 may have the same or different types of hypervisors.

[0076] A computing instance can be a virtual machine instance or a bare metal instance. In Figure 2, computing instance 268 on host machine 202 and computing instance 274 on host machine 208 are examples of virtual machine instances. Host machine 206 is an example of a bare metal instance provided to a customer.

[0077] In some cases, an entire host machine may be provisioned to a single customer, and all of the one or more computing instances (virtual machine or bare metal instances) hosted by that host machine belong to the same customer. In other cases, a host machine may be shared among multiple customers (i.e., multiple tenants). In such a multi-tenant scenario, a host machine may host virtual machine computing instances that belong to different customers. These computing instances may be members of different VCNs for different customers. In certain embodiments, bare metal computing instances are hosted by bare metal servers without a hypervisor. When a bare metal computing instance is provisioned, a single customer or tenant maintains control of the physical CPU, memory, and network interfaces of the host machine that hosts the bare metal instance, and the host machine is not shared with other customers or tenants.

[0078] As previously mentioned, each computing instance that is part of a VCN is associated with a VNIC that enables the computing instance to be a member of a subnet of the VCN. The VNIC associated with a computing instance facilitates communication of packets or frames to and from the computing instance. The VNIC is associated with the computing instance when the computing instance is created. In a particular embodiment, for a computing instance executed by a host machine, the VNIC associated with the computing instance is executed by the NVD connected to the host machine. For example, in FIG. 2, the host machine 202 executes a virtual machine computing instance 268 associated with a VNIC 276, which is executed by the NVD 210 connected to the host machine 202. As another example, the bare metal instance 272 hosted by the host machine 206 is associated with a VNIC 280, which is executed by the NVD 212 connected to the host machine 206. As yet another example, the VNIC 284 is associated with the computing instance 274 executed by the host machine 208, which is executed by the NVD 212 connected to the host machine 208.

[0079] For a computing instance hosted by a host machine, the NVD connected to that host machine also runs a VCN VR corresponding to the VCN of which the computing instance is a member. For example, in the embodiment shown in Figure 2, NVD 210 runs VCN VR 277 corresponding to the VCN of which computing instance 268 is a member. NVD 212 may also run one or more VCN VRs 283 corresponding to the VCNs corresponding to the computing instances hosted by host machines 206 and 208.

[0080] A host machine may include one or more network interface cards (NICs) that allow the host machine to be connected to other devices. The NICs on a host machine may provide one or more ports (or interfaces) that allow the host machine to be communicatively connected to another device. For example, a host machine may be connected to an NVD using one or more ports (or interfaces) provided on the host machine and the NVD. A host machine may also be connected to other devices, such as another host machine.

[0081] 2, host machine 202 is connected to NVD 210 using link 220 extending between port 234 provided by NIC 232 of host machine 202 and port 236 of NVD 210. Host machine 206 is connected to NVD 212 using link 224 extending between port 246 provided by NIC 244 of host machine 206 and port 248 of NVD 212. Host machine 208 is connected to NVD 212 using link 226 extending between port 252 provided by NIC 250 of host machine 208 and port 254 of NVD 212.

[0082] The NVDs are then connected via communication links to top-of-the-rack (TOR) switches, which are connected to a physical network 218 (also referred to as a switch fabric). In certain embodiments, the links between the host machines and the NVDs and between the NVDs and the TOR switches are Ethernet links. For example, in FIG. 2, NVDs 210 and 212 are connected to TOR switches 214 and 216, respectively, using links 228 and 230. In certain embodiments, links 220, 224, 226, 228, and 230 are Ethernet links. The collection of host machines and NVDs connected to a TOR may be referred to as a rack.

[0083] The physical network 218 provides a communications fabric that allows the TOR switches to communicate with each other. The physical network 218 can be a multi-tier network. In a particular implementation, the physical network 218 is a multi-tier Clos network of switches, with the TOR switches 214 and 216 representing leaf-level nodes of the multi-tier and multi-node physical switching network 218. A variety of Clos network configurations are possible, including, but not limited to, two-tier networks, three-tier networks, four-tier networks, five-tier networks, and generally "n"-tier networks. An example Clos network is shown in FIG. 5 and described below.

[0084] Various connection configurations are possible between host machines and NVDs, including one-to-one, many-to-one, and one-to-many. In a one-to-one implementation, each host machine is connected to its own separate NVD. For example, in FIG. 2, host machine 202 is connected to NVD 210 via NIC 232 on host machine 202. In a many-to-one configuration, multiple host machines are connected to a single NVD. For example, in FIG. 2, host machines 206 and 208 are connected to the same NVD 212 via NICs 244 and 250, respectively.

[0085] In a one-to-many configuration, one host machine is connected to multiple NVDs. Figure 3 shows an example in CSPI 300 where a host machine is connected to multiple NVDs. As shown in Figure 3, a host machine 302 includes a network interface card (NIC) 304 that includes multiple ports 306 and 308. The host machine 300 is connected to a first NVD 310 via port 306 and link 320, and to a second NVD 312 via port 308 and link 322. The ports 306 and 308 may be Ethernet ports, and the links 320 and 322 between the host machine 302 and the NVDs 310 and 312 may be Ethernet links. The NVD 310 is then connected to a first TOR switch 314, and the NVD 312 is connected to a second TOR switch 316. The links between the NVDs 310 and 312 and the TOR switches 314 and 316 may be Ethernet links. TOR switches 314 and 316 represent layer 0 switching devices in a multi-tiered physical network 318 .

[0086] 3 provides two separate physical network paths from the physical switch network 318 to the host machine 302. The first path is via the TOR switch 314 to the NVD 310 to the host machine 302, and the second path is via the TOR switch 316 to the NVD 312 to the host machine 302. The separate paths increase the availability of the host machine 302 (referred to as high availability). If there is a problem with either path (e.g., if a link on either path is down) or if there is a problem with a device (e.g., if a particular NVD is not functioning), the other path can be used to communicate with the host machine 302.

[0087] In the configuration shown in Figure 3, the host machine is connected to two different NVDs using two different ports provided by the host machine's NIC. In other embodiments, the host machine may include multiple NICs that allow the host machine to be connected to multiple NVDs.

[0088] Returning to Figure 2, an NVD is a physical device or component that performs one or more network and / or storage virtualization functions. An NVD can be any device with one or more processing units (e.g., CPU, network processing unit (NPU), FPGA, packet processing pipeline), memory including cache, and ports. Various virtualization functions may be performed by software / firmware executed by the NVD's one or more processing units.

[0089] NVDs can be implemented in a variety of different forms. For example, in a particular embodiment, the NVD is implemented as an interface card, called a smart NIC or intelligent NIC, with an on-board built-in processor. A smart NIC is a separate device from the NIC on the host machine. In FIG. 2, NVDs 210 and 212 can be implemented as smart NICs connected to host machine 202, and host machines 206 and 208, respectively.

[0090] However, smart NICs are only one example of an NVD implementation. Various other implementations are possible. For example, in some other implementations, the NVD or one or more functions performed by the NVD may be incorporated into or performed by one or more host machines, one or more TOR switches, and other components of CSPI200. For example, the NVD may be implemented in a host machine and the functions performed by the NVD may be performed by the host machine. As another example, the NVD may be part of a TOR switch, or the TOR switch may be configured to perform the functions performed by the NVD, allowing the TOR switch to perform various complex packet transformations used for public clouds. A TOR that performs the functions of an NVD may be referred to as a smart TOR. In still other implementations, virtual machine (VM) instances rather than bare metal (BM) instances are provided to customers, and the functions performed by the NVD may be implemented within the hypervisor of the host machine. In some other implementations, some of the functions of the NVD may be offloaded to a centralized service running on a set of host machines.

[0091] In certain embodiments, such as when implemented as a smart NIC as shown in FIG. 2, the NVD may have multiple physical ports that allow it to connect to one or more host machines and one or more TOR switches. Ports on the NVD may be classified as host-side ports (also called "south ports") or network-side or TOR-side ports (also called "north ports"). The host-side ports of the NVD are the ports used to connect the NVD to a host machine. Examples of host-side ports in FIG. 2 include port 236 of NVD 210, and ports 248 and 254 of NVD 212. The network-side ports of the NVD are the ports used to connect the NVD to a TOR switch. Examples of network-side ports in FIG. 2 include port 256 of NVD 210 and port 258 of NVD 212. As shown in FIG. 2, the NVD 210 is connected to the TOR switch 214 using link 228 that extends from port 256 of NVD 210 to the TOR switch 214. Similarly, the NVD 212 is connected to the TOR switch 216 using a link 230 that extends from a port 258 of the NVD 212 to the TOR switch 216 .

[0092] The NVD may receive packets and frames (e.g., packets and frames generated by computing instances hosted by the host machine) from a host machine via a host-side port, perform necessary packet processing, and then forward the packets and frames to a TOR switch via a network-side port of the NVD. The NVD may receive packets and frames from a TOR switch via a network-side port of the NVD, perform necessary packet processing, and then forward the packets and frames to a host machine via a host-side port of the NVD.

[0093] In certain embodiments, there may be multiple ports and associated links between the NVD and the TOR switch. These ports and links may be aggregated to form a link aggregator group (called a LAG) of multiple ports or links. Link aggregation allows multiple physical links between two endpoints (e.g., between the NVD and the TOR switch) to be treated as one logical link. All physical links within a particular LAG may operate in full-duplex mode at the same speed. LAGs help to increase the bandwidth and reliability of the connection between the two endpoints. If one of the physical links in the LAG goes down, the traffic is dynamically and transparently reassigned to one of the other physical links in the LAG. The aggregated physical links provide higher bandwidth than individual links. Multiple ports associated with a LAG are treated as a single logical port. Traffic can be load balanced among the multiple physical links in the LAG. One or more LAGs can be configured between two endpoints. The two endpoints may be between the NVD and the TOR switch, between a host machine and the NVD, etc.

[0094] The NVD implements or performs network virtualization functions. These functions are performed by software / firmware executed by the NVD. Examples of network virtualization functions include, but are not limited to, packet encapsulation and decapsulation functions, functions for creating VCN networks, functions for implementing network policies such as VCN security list (firewall) functions, functions for facilitating routing and forwarding of packets to and from compute instances in the VCN, and the like. In a particular embodiment, upon receiving a packet, the NVD is configured to execute a packet processing pipeline to process the packet and determine how to forward or route the packet. As part of this packet processing pipeline, the NVD may execute one or more virtual functions associated with the overlay network, such as running VNICs associated with cis in the VCN, running virtual routers (VRs) associated with the VCN, encapsulating and decapsulating packets to facilitate forwarding or routing within the virtual network, running specific gateways (e.g., local peering gateways), implementing security lists, network security groups, network address translation (NAT) functions (e.g., translating public IPs to private IPs per host), throttling functions, and other functions.

[0095] In certain embodiments, the packet processing data path within the NVD may include multiple packet pipelines, each consisting of a series of packet transformation stages. In a particular implementation, upon receiving a packet, the packet is parsed and classified into a single pipeline. The packet is then processed step-by-step in a linear fashion until it is either dropped or transmitted through an interface of the NVD. These stages provide basic functional packet processing building blocks (e.g., validate headers, apply throttling, insert new layer 2 headers, apply L4 firewall, VCN encapsulation / decapsulation, etc.), so that existing stages can be combined to build new pipelines or new functionality can be added by creating new stages and inserting them into existing pipelines.

[0096] The NVD can perform both control plane and data plane functions corresponding to the control and data planes of the VCN. Examples of the VCN control plane are also shown in Figures 12, 13, 14, and 15 (see references 1216, 1316, 1416, and 1516) and described below. Examples of the VCN data plane are also shown in Figures 12, 13, 14, and 15 (see references 1218, 1318, 1418, and 1518) and described below. The control plane functions include functions used to configure the network (e.g., setting routes and route tables, configuring VNICs) that control how data is forwarded. In certain embodiments, a VCN control plane is provided that centrally computes all overlay-to-substrate mappings and exposes them to virtual network edge devices such as the NVD and various gateways such as DRGs, SGWs, IGWs, etc. Firewall rules can also be exposed using the same mechanism. In certain embodiments, the NVD retrieves only mappings that are relevant to the NVD. The data plane functions include the actual routing / forwarding of packets based on the configurations set using the control plane. The VCN data plane is implemented by encapsulating customer network packets before they traverse the underlying network. The encapsulation / decapsulation functions are implemented in the NVD. In a particular embodiment, the NVD is configured to intercept all network packets entering and leaving the host machine and perform network virtualization functions.

[0097] As mentioned above, the NVD performs various virtualization functions such as VNICs and VCN VRs. The NVD may perform VNICs associated with computing instances hosted by one or more host machines connected to the VNICs. For example, as shown in FIG. 2, the NVD 210 performs functions of a VNIC 276 associated with a computing instance 268 hosted by a host machine 202 connected to the NVD 210. As another example, the NVD 212 performs VNICs 280 associated with a bare metal computing instance 272 hosted by a host machine 206 and VNICs 284 associated with a computing instance 274 hosted by a host machine 208. The host machines may host computing instances belonging to different VCNs that belong to different customers, and the NVDs connected to the host machines may perform VNICs (i.e., perform VNIC-related functions) corresponding to the computing instances.

[0098] The NVDs also run VCN virtual routers corresponding to the VCNs of the computing instances. For example, in the embodiment shown in FIG. 2, NVD 210 runs VCN VR 277 corresponding to the VCN to which computing instance 268 belongs. NVD 212 runs one or more VCN VRs 283 corresponding to one or more VCNs to which computing instances hosted by host machines 206 and 208 belong. In a particular embodiment, a VCN VR corresponding to that VCN is run by all NVDs connected to a host machine that hosts at least one computing instance that belongs to that VCN. If a host machine hosts computing instances that belong to different VCNs, the NVDs connected to that host machine may run VCN VRs corresponding to those different VCNs.

[0099] In addition to the VNICs and VCN VRs, the NVD may include one or more hardware components that run various software (e.g., daemons) and facilitate various network virtualization functions performed by the NVD. For simplicity, these various components are grouped together as a "packet processing component" as shown in FIG. 2. For example, NVD 210 includes packet processing component 286, and NVD 212 includes packet processing component 288. For example, the packet processing component of the NVD may include a packet processor configured to interact with the ports and hardware interfaces of the NVD to monitor all packets received by the NVD and communicated using the NVD, and store network information. The network information may include, for example, network flow information identifying various network flows processed by the NVD, and per-flow information (e.g., per-flow statistics). In certain embodiments, the network flow information may be stored per VNIC. The packet processor may perform per-packet operations as well as implement stateful NAT and L4 firewall (FW). As another example, the packet processing component may include a replication agent configured to replicate information stored by the NVD to one or more different replication target stores. As yet another example, the packet processing component may include a logging agent configured to perform logging functions for the NVD. The packet processing component may also include software that monitors the performance and health of the NVD, as well as software that monitors the status and health of other components connected to the NVD.

[0100] FIG. 1 illustrates components of an example virtual or overlay network, including a VCN, a subnet in the VCN, compute instances deployed on the subnet, VNICs associated with the compute instances, VRs of the VCN, and a set of gateways configured for the VCN. The overlay components illustrated in FIG. 1 may be executed or hosted by one or more physical components illustrated in FIG. 2. For example, compute instances in a VCN may be executed or hosted by one or more host machines illustrated in FIG. 2. For a compute instance hosted by a host machine, the VNICs associated with that compute instance are typically executed by the NVD connected to that host machine (i.e., the VNIC functionality is provided by the NVD connected to that host machine). The VCN VR functionality of the VCN is executed by all NVDs connected to the host machines that host or execute the compute instances that are part of that VCN. The gateways associated with a VCN may be executed by one or more different types of NVDs. For example, certain gateways may be executed by smart NICs, while other gateways may be executed by one or more host machines or other implementations of NVDs.

[0101] As mentioned earlier, compute instances in a customer VCN can communicate with a variety of different endpoints. The endpoints may be in the same subnet as the source compute instance, they may be in the same VCN as the source compute instance but in a different subnet, or they may be outside the VCN of the source compute instance. These communications are facilitated using the VNICs associated with the compute instance, the VCN VRs, and the gateways associated with the VCN.

[0102] Communication between two compute instances on the same subnet in a VCN is facilitated using VNICs associated with the source and destination compute instances. The source and destination compute instances can be hosted on the same host machine or on different host machines. A packet originating from a source compute instance may be forwarded from the host machine hosting the source compute instance to an NVD connected to that host machine. In the NVD, the packet is processed using a packet processing pipeline. This may include running the VNIC associated with the source compute instance. Because the destination endpoint of the packet is in the same subnet, running the VNIC associated with the source compute instance forwards the packet to the NVD running the VNIC associated with the destination compute instance, which processes the packet and forwards it to the destination compute instance. The VNICs associated with the source and destination compute instances may run on the same NVD (e.g., when both the source and destination compute instances are hosted by the same host machine) or on different NVDs (e.g., when the source and destination compute instances are hosted by different host machines connected to different NVDs). The VNICs may use the routing / forwarding tables stored by the NVD to determine the next hop of the packet.

[0103] When communicating a packet from a compute instance in a subnet to an endpoint in a different subnet in the same VCN, the packet originating from the source compute instance is communicated from the host machine hosting the source compute instance to the NVD that is connected to that host machine. In the NVD, the packet is processed using a packet processing pipeline, which may include running one or more VNICs and VRs associated with the VCN. For example, as part of the packet processing pipeline, the NVD executes or invokes a function that corresponds to the VNIC associated with the source compute instance (also referred to as executing the VNIC). The function performed by the VNIC may include checking the VLAN tag on the packet. Because the destination of the packet is outside the subnet, a VCN VR function is then invoked and executed by the NVD. The VCN VR then routes the packet to the NVD that executes the VNIC associated with the destination compute instance. The VNIC associated with the destination compute instance then processes the packet and forwards the packet to the destination compute instance. The VNICs associated with the source and destination compute instances may run on the same NVD (e.g., when both the source and destination compute instances are hosted by the same host machine) or on different NVDs (e.g., when the source and destination compute instances are hosted by different host machines that are connected to different NVDs).

[0104] If the packet destination is outside the VCN of the source compute instance, the packet originating from the source compute instance is communicated from the host machine hosting the source compute instance to the NVD connected to that host machine. The NVD runs the VNIC associated with the source compute instance. Because the packet's destination endpoint is outside the VCN, the packet is processed by the VCN VR for that VCN. The NVD invokes VCN VR functions, which result in the packet being forwarded to an NVD running the appropriate gateway associated with the VCN. For example, if the destination is an endpoint in a customer's on-premises network, the packet may be forwarded by the VCN VR to an NVD running a DRG gateway configured for the VCN. The VCN VR may run on the same NVD as the NVD running the VNIC associated with the source compute instance, or by a different NVD. The gateway may be run by the NVD, which may be a smart NIC, a host machine, or any other NVD implementation. The packet is then processed by the gateway and forwarded to the next hop, facilitating the packet to the intended destination endpoint. 2, a packet originating from computing instance 268 may be communicated from host machine 202 (using NIC 232) over link 220 to NVD 210. In NVD 210, VNIC 276 is called out because it is the VNIC associated with source computing instance 268. VNIC 276 is configured to examine information encapsulated within the packet, determine a next hop for forwarding the packet to facilitate communication of the packet to its intended destination endpoint, and forward the packet to the determined next hop.

[0105] Computing instances deployed in a VCN can communicate with various endpoints. These endpoints can include endpoints hosted by CSPI200 and endpoints external to CSPI200. Endpoints hosted by CSPI200 can include instances in the same VCN or other VCNs. These VCNs can be customer VCNs or VCNs not belonging to the customer. Communications between endpoints hosted by CSPI200 can be performed over physical network 218. Computing instances can also communicate with endpoints not hosted by CSPI200 or external to CSPI200. Examples of these endpoints include endpoints in a customer's on-premise network or datacenter, or public endpoints accessible over a public network such as the Internet. Communications with endpoints external to CSPI200 can be performed over a public network (e.g., the Internet) (not shown in FIG. 2) or a private network (not shown in FIG. 2) using various communication protocols.

[0106] The architecture of CSPI 200 shown in FIG. 2 is merely an example and is not limiting. Variations, substitutions, and modifications are possible in alternative embodiments. For example, in some implementations, CSPI 200 may include more or fewer systems or components than those shown in FIG. 2, may combine two or more systems, or may have different configurations or arrangements of systems. The systems, subsystems, and other components shown in FIG. 2 may be implemented using hardware, or a combination thereof, with software (e.g., code, instructions, programs) executed by one or more processing units (e.g., processors, cores) of the respective systems. The software may be stored in a non-transitory storage medium (e.g., a memory device).

[0107] FIG. 4 illustrates connections between host machines and NVDs to provide I / O virtualization to support multi-tenancy according to certain embodiments. As shown in FIG. 4, host machine 402 runs hypervisor 404 to provide a virtualized environment. Host machine 402 runs two virtual machine instances: VM1 406 belonging to customer / tenant #1 and VM2 408 belonging to customer / tenant #2. Host machine 402 includes a physical NIC 410 connected to NVD 412 via link 414. Each computing instance is connected to a VNIC executed by NVD 412. In the embodiment of FIG. 4, VM1 406 is connected to VNIC-VM1 420 and VM2 408 is connected to VNIC-VM2 422.

[0108] 4, NIC 410 includes two logical NICs: logical NIC A 416 and logical NIC B 418. Each virtual machine is connected to and configured to run with its own logical NIC. For example, VM1 406 is connected to logical NIC A 416, and VM2 408 is connected to logical NIC B 418. Although host machine 402 includes only one physical NIC 410 that is shared by multiple tenants, because of the logical NICs, each tenant's virtual machine sees it as having its own host machine and NIC.

[0109] In a particular embodiment, each logical NIC is assigned its own VLAN ID. Thus, logical NIC A 416 for tenant #1 is assigned a particular VLAN ID, and logical NIC B 418 for tenant #2 is assigned another VLAN ID. When a packet is communicated from VM1 406, a tag assigned to tenant #1 is attached to the packet by the hypervisor, and the packet is then communicated from host machine 402 to NVD 412 via link 414. Similarly, when a packet is communicated from VM2 408, a tag assigned to tenant #2 is attached to the packet by the hypervisor, and the packet is then communicated from host machine 402 to NVD 412 via link 414. Thus, a packet 424 communicated from host machine 402 to NVD 412 includes an associated tag 426 that identifies the particular tenant and associated VM. For a packet 424 received from a host machine 402, the NVD uses the tag 426 associated with the packet to determine whether the packet should be processed by VNIC-VM1 420 or VNIC-VM2 422. The packet is then processed by the corresponding VNIC. The configuration shown in Figure 4 allows each tenant's computing instance to perceive it as owning its own host machine and NIC. The setup shown in Figure 4 provides I / O virtualization to support multi-tenancy.

[0110] FIG. 5 illustrates a simplified block diagram of a physical network 500 according to a particular embodiment. The embodiment illustrated in FIG. 5 is configured as a Clos network. A Clos network is a particular type of network topology designed to provide connection redundancy while maintaining high bisection bandwidth and maximum resource utilization. A Clos network is a type of non-blocking, multi-stage, or multi-tier switching network, where the number of stages or tiers can be 2, 3, 4, 5, etc. The embodiment illustrated in FIG. 5 is a three-tier network including tier 1, tier 2, and tier 3. A TOR switch 504 represents a tier 0 switch in a Clos network. One or more NVDs are connected to a TOR switch. A tier 0 switch is also referred to as an edge device of the physical network. A tier 0 switch is connected to a tier 1 switch, also referred to as a leaf switch. In the embodiment illustrated in FIG. 5, a set of "n" tier 0 TOR switches are connected to a set of "n" tier 1 switches, together forming a pod. Each tier 0 switch in a pod is interconnected to all tier 1 switches in the pod, but there is no switch connectivity between pods. In a particular implementation, the two pods are referred to as blocks. Each block is served by or connected to a set of "n" layer 2 switches (sometimes referred to as spine switches). There can be multiple blocks in a physical network topology. The layer 2 switches are in turn connected to "n" layer 3 switches (sometimes referred to as super spine switches). Communication of packets through the physical network 500 is typically performed using one or more layer 3 communication protocols. Typically, all layers of the physical network except the TOR layer are n-way redundant, thus providing high availability. To enable scaling of the physical network, policies can be specified on pods and blocks to control visibility between switches in the physical network.

[0111] A feature of Clos networks is that there is a fixed maximum number of hops to go from one tier 0 switch to another tier 0 switch (or from an NVD connected to a tier 0 switch to another NVD connected to a tier 0 switch). For example, in a three-tier Clos network, if the source NVD and the target NVD are connected to the leaf tier of the Clos network, a maximum of seven hops are required for a packet to go from one NVD to another NVD. Similarly, in a four-tier Clos network, if the source NVD and the target NVD are connected to the leaf tier of the Clos network, a maximum of nine hops are required for a packet to go from one NVD to another NVD. Thus, the Clos network architecture maintains consistent latency throughout the network, which is important for intra-datacenter and inter-datacenter communications. Clos topologies are horizontally scalable and cost-effective. The bandwidth / throughput capacity of the network can be easily increased by adding switches at various tiers (e.g., adding leaf and spine switches) and by increasing the number of links between switches at adjacent tiers.

[0112] In a particular embodiment, each resource in the CSPI is assigned a unique identifier called a Cloud Identifier (CID), which is included as part of the resource's information and can be used to manage the resource, for example, through a console, API, etc. An example syntax for a CID is: ocid1.<RESOURCE TYPE> . <realm>.[REGION][.FUTURE USE].<UNIQUE ID> ocid1: A literal string indicating the CID version. resource type: The type of resource (for example, instance, volume, VCN, subnet, user, group, etc.). realm: The realm the resource resides in. Example values ​​include "c1" for a commercial realm, "c2" for a government cloud realm, "c3" for a federal cloud realm, etc. Each realm may have its own domain name. region: The region the resource is in. This may be blank if a region does not apply to the resource. future use: Reserved for future use. unique ID: The unique part of the ID, the format can vary depending on the type of resource or service.

[0113] FIG. 6 illustrates a block diagram of a cloud infrastructure 600 incorporating a CLOS network arrangement, according to certain embodiments. The cloud infrastructure 600 includes multiple racks (e.g., rack 1 610, rack 2, 620). Each rack includes multiple host machines (hereinafter also referred to as hosts). Rack 1 610 is shown to include two host machines, namely, host 1-A 612 and host 1-B 614, and rack 2 620 is shown to include two host machines, namely, host 2-A 622 and host 2-B 624. It is understood that the illustration of FIG. 6 (i.e., each rack includes two host machines) is for illustrative purposes and not limiting. For example, a cloud infrastructure may include two or more racks, and each rack may include two or more host machines. Additionally, it is noted that there is no limitation that there are the same number of hosts in each rack. Rather, a rack may include more or fewer host machines than another rack includes.

[0114] Each host machine includes multiple graphics processing units (GPUs). For example, host machine 1-A 612 includes N GPUs (e.g., GPU1, 613). Additionally, while the description of FIG. 6 depicts each host machine including the same number of GPUs, i.e., N GPUs, it is understood that this is for illustrative purposes and not limiting, i.e., each host machine may include a different number of GPUs. Each rack includes a top-of-rack (TOR) switch communicatively coupled to the GPUs hosted on the host machines in the rack. For example, rack 1 610 includes a TOR switch (i.e., TOR1) 616 communicatively coupled to host machines host 1-A, 612 and host 1-B, 614, while rack 2 620 includes a TOR switch (i.e., TOR2) 626 communicatively coupled to host machines host 2-A, 622 and host 2-K, 624. It is understood that the TOR switches (i.e., TOR1 616 and TORM 626) shown in Figure 6 each include N ports that are used to communicatively couple the TOR switch to the N GPUs hosted on each host machine included in the rack. The coupling of the TOR switches and GPUs shown in Figure 6 is for illustrative purposes and not limiting. For example, in some embodiments, the TOR switch may have multiple ports, each port corresponding to a GPU on each host machine, i.e., a GPU on a host machine may be connected to a unique port of the TOR via a communication link.

[0115] The TOR switches in each rack are communicatively coupled to multiple spine switches, e.g., spine switch 1 630 and spine switch P 640. For example, as shown in FIG. 6, TOR1 616 is connected to spine switch 1 630 via two links and to spine switch P 640 via another two links, respectively. Information sent from a particular TOR switch to a spine switch is referred to herein as communication occurring over an uplink, while information sent from a spine switch to a TOR switch is referred to herein as communication occurring over a downlink. According to some embodiments, the TOR switches and spine switches are connected in a CLOS network arrangement (e.g., a multi-stage switching network), with each TOR switch forming a "leaf" node in the CLOS network.

[0116] According to some embodiments, GPUs included in a host machine execute tasks related to machine learning. In such a setup, a single task may be executed / distributed across a large number of GPUs (e.g., 64 GPUs), potentially across multiple host machines and multiple racks. Since all these GPUs are working on the same task (i.e., workload), they all need to communicate with each other in a time-synchronized manner. Furthermore, at any given time, the GPUs are either in a computing mode or a communication mode, i.e., the GPUs communicate with each other at approximately the same time. The speed of the workload is determined by the speed of the slowest GPU.

[0117] Typically, equal-cost multipath (ECMP) routing is utilized to route packets from a source GPU to a destination GPU. In ECMP routing, when there are multiple equal-cost paths that can be used to route traffic from a sender to a receiver, a selection technique is used to select a particular path. Thus, at the network device receiving the traffic (e.g., a TOR switch or a spine switch), a selection algorithm is used to select the outgoing link that will be used to forward the traffic from the network device to the subsequent device. This outgoing link selection is done at each network device in the path from the sender to the receiver. Hash-based selection is a widely used ECMP selection technique, where the hash can be based, for example, on the packet's 4-tuple (e.g., source port, destination port, source IP, destination IP).

[0118] ECMP routing is a flow-aware routing technique, where each flow (i.e., a stream of data packets) is hashed to the same path for the duration of the flow. Thus, packets in a flow are forwarded out of a network device using a specific outgoing port / link. This is typically done to ensure that packets in a flow arrive in order, i.e., no packet reordering is required. However, ECMP routing is not aware of bandwidth (or throughput); that is, TOR and spine switches perform statistical flow-aware (throughput-unaware) ECMP load balancing of flows over parallel links.

[0119] Standard ECMP routing (i.e., flow-only aware routing) has the problem that flows received by a network device over two separate incoming links may hash to the same outgoing link, which may result in flow collisions. For example, consider a situation where two flows arrive over two separate 100G incoming links, and each flow hashes to the same 100G outgoing link. In such a situation, congestion (i.e., flow collisions) occur and packets are dropped because the incoming bandwidth is 200G while the outgoing bandwidth is 100G. As shown in FIG. 6, there are two flows: flow 1 641, which is directed from a first GPU on host machine Host1-A, 612 to the TOR switch 616, and flow 2 643, which is directed from another GPU on host machine 614 to the TOR switch 616. Note that the two flows are directed to the TOR switch on separate links. The capacity (bandwidth) of all links shown in FIG. 6 is assumed to be 100G. If the TOR switch 616 runs an ECMP routing algorithm, the two flows may be hashed to use the same outgoing link of the TOR (e.g., link 650 connecting the TOR switch 616 to the spine switch 630). In this case, a collision occurs between the two flows (represented by an "X" mark) and the packet is dropped.

[0120] Such collision scenarios are a common problem for all types of traffic, regardless of protocol. For example, TCP is intelligent in that if a packet is dropped and the sender did not receive an acknowledgment for the dropped packet, the packet will be retransmitted. However, for Remote Direct Memory Access (RDMA) type traffic, the situation is worse. RDMA networks do not use TCP for various reasons (e.g. TCP has complex logic and is not suitable for low latency and high performance). RDMA networks use protocols such as RDMA over InfiniBand and RDMA over Converged Ethernet (RoCE). RoCE has congestion control algorithms, and when the sender identifies congestion occurring or a dropped packet, the sender slows down the rate at which packets are sent. In the case of a dropped packet, not only the dropped packet but also several packets around the dropped packet are retransmitted, further consuming available bandwidth and degrading performance.

[0121] The flow collision problem is a significant issue for workload execution, e.g., GPU workloads, due to strict time synchronization requirements. For example, GPUs may execute machine learning tasks (i.e., workloads) that require all GPUs to communicate with each other in a time-synchronized manner. Furthermore, customer workloads may be of different types, each with different requirements. For example, a first workload (e.g., GPU workloads) may be bandwidth sensitive, while a second workload (e.g., High Performance Computing (HPC) workloads) may be delay or latency sensitive. Furthermore, a customer may wish to select host machines to execute a workload based on the application. For example, for workloads that are delay (or latency) sensitive, a customer may wish to select host machines that are physically close to each other (e.g., contained in the same rack). As another example, a customer may wish to place workloads in anti-affinity groups, i.e., distribute host machines across different racks, to achieve higher availability in the event of a network failure. Typically, host machines are assigned to customers (to execute their respective workloads) in an arbitrary (random) manner. This increases the likelihood of increased traffic congestion, resulting in reduced workload throughput. Furthermore, there is currently no mechanism available to provide host machine locality information to customers.

[0122] Below, techniques are described to overcome the above problems. Specifically, the techniques described herein provide a hierarchy of host machine locality information to customers, and allow the customers to select specific host machines (based on the provided locality information) to run their workloads. For example, some embodiments of the present disclosure enable customers to reduce application-to-service latency by "placing" workloads on nearby host machines. Additionally, customers can use the locality information to place workloads for higher anti-affinity, thereby achieving higher resiliency by reducing resource sharing consequences.

[0123] Referring to Figure 7, an exemplary configuration of a rack 700 is shown in accordance with certain embodiments. As shown in Figure 7, the rack 700 includes two host machines, namely, host 1-A 710 and host 1-B 720. Although the rack 700 is shown to include two host machines, it is understood that the rack 700 may include more host machines. Each host machine may further include multiple GPUs and multiple CPUs.

[0124] The host machines (i.e., Host1-A 710 and Host1-B 720) are communicatively coupled to a network fabric via a top-of-rack switch, i.e., TOR1 750. This network fabric is also referred to herein as the front-end network of the rack 700 and may correspond to an external network. The host machine, i.e., Host1-A 710, is connected to the front-end network via a network interface card (NIC) 730 and a NVD 735 (i.e., a network virtualizer) that is coupled to TOR1 750. The host machine, i.e., Host1-B 720, is connected to the front-end network via a network interface card (NIC) 740 and a network virtualizer 745 that is coupled to TOR1 750. The host machines Host1-A 710 and Host1-B 720 are connected to a QoS-enabled back-end network on the other side. The QoS-enabled back-end network may correspond to a GPU cluster network as shown in FIG. 6. The host machine 1-A 710 is connected to the TOR2 switch 760 via another NIC 765, which communicatively couples the host machine to the back-end network. Similarly, the host machine 1-B 720 is connected to the TOR2 switch 760 via a NIC 780, which communicatively couples the host machine to the back-end network.

[0125] According to some embodiments, host machines are not aware of the physical topology of the network, i.e., a particular host machine is not aware of the physical location / position of other host machines in the network. For example, referring to FIG. 6, host machine 1-A 612 is not aware that host machine 1-B 614 is actually contained in the same rack (i.e., rack 1 610) and located behind the same TOR switch (i.e., TOR1 616). However, the network control plane is aware of the overall physical topology of the host machines. In one implementation, the network control plane exposes such locality information to the host machines to achieve traffic locality and avoid unnecessary traffic congestion. Doing so has a significant impact on the performance of the workload.

[0126] In some embodiments, the network control plane utilizes an instance metadata service (IMDS) to expose (and store) metadata information (e.g., locality information) to host machines. Such metadata information may be exposed to host machines via respective NVDs associated with the host machines. For example, with reference to FIG. 7, locality information is exposed (via IMDS) to host 1-A 710 via NVD 735, while locality information is exposed (via IMDS) to host 1-B 720 via NVD 745. As will now be described with reference to FIGS. 8 and 10, it will be appreciated that the locality information may include metadata indicating a hierarchy of the host machine's locality information. It will be appreciated that each host machine may query the IMDS to obtain metadata information associated with the host machine.

[0127] FIG. 8 is a schematic diagram illustrating a hierarchy of host machine locality information 850, according to certain embodiments. For purposes of illustration, each rack in FIG. 8 is shown to include two host machines. For example, rack 1 801 includes two host machines H1 and H2 (associated with a TOR switch, i.e., TOR1), rack 2 803 includes two host machines H3 and H4 (associated with a TOR switch, i.e., TOR2), rack 3 811 includes two host machines H5 and H6 (associated with a TOR switch, i.e., TOR3), and rack 4 813 includes two host machines H7 and H8 (associated with a TOR switch, i.e., TOR4). Similarly, racks 5 821 through 8 833 are shown to include two host machines each. It is understood that each rack is not limited to including two host machines. Rather, each rack may include a larger number of host machines, and further, the number of host machines included in a rack may vary as compared to the number of host machines included in another rack.

[0128] According to some embodiments, a collection of racks may comprise a block. For example, rack 1 (801) and rack 2 (803) may comprise block 1 805, while rack 3 (811) and rack 4 (813) may comprise block 2 (815). Similarly, rack 5 (821) and rack 6 (823) may comprise block 3 (825), while rack 7 (831) and rack 8 (833) may comprise block 4 (835). Furthermore, a collection of blocks may comprise a building. For example, block 1 805 and block 2 815 may comprise building 1 820, while block 3 825 and block 4 835 may comprise building 2 840. A collection of buildings may comprise an availability domain. For example, as shown in FIG. 8, building 1 820 and building 2 840 may be included in availability domain 1 850.

[0129] It is understood that host machines included in the same rack, e.g., H1 and H2 included in rack 1 801, share a top-of-rack (i.e., TOR) switch associated with the rack. Furthermore, a block corresponds to racks that are located near each other (i.e., geographically close) (e.g., rack 1 801 and rack 2 803 included in block 1 805 are located close to each other) as opposed to racks that are located far from each other, e.g., rack 1 801 (included in block 1 805) and rack 4 (included in block 2). Furthermore, a collection of buildings may correspond to an availability domain (e.g., data center), i.e., building 1 820 and building 2 840 included in availability domain 1 850. Thus, as described below with reference to FIG. 9, the locality information of host machines has multiple levels of hierarchical information, such as rack location, block location, building location, availability domain location, etc.

[0130] FIG. 9 illustrates an exemplary tree diagram showing levels (i.e., hierarchies) of host machine locality information, according to certain embodiments. The hierarchical locality information is displayed in order of decreasing latency. As illustrated in FIG. 9, level 1 of the hierarchical locality information includes multiple availability domains (ADs), e.g., AD1, AD2, ... ADK. At level 2, each availability domain may include multiple buildings, e.g., Building 1, Building 2, ... Building L, contained in availability domain 2. At level 3, each building may include multiple blocks, e.g., Block 1, Block 2, ... Block M, contained in building 2. Finally, at level 4 (i.e., the level with the least amount of latency), each block may include one or more racks, and each rack includes one or more host machines. For example, as illustrated in FIG. 9, block 2 includes multiple racks, i.e., Rack 1, Rack 2 ... Rack N. The hierarchical locality information for a particular host in rack 2 includes information identifying the nodes in the locality tree shown in FIG. 9 between the root node and the location of the host (e.g., for host A, the hierarchical locality information includes Availability_domain_2→Building_2→Block_2→Rack_2).

[0131] According to some embodiments, each host machine can communicate with an instance metadata service (IMDS) to obtain hierarchical locality information associated with the host machine. For example, each host machine is associated with an NVD in which applications can run to communicate with private IP addresses (e.g., addresses in the IMDS) to obtain hierarchical locality information. In one implementation, the host machine can obtain an encoded array of hierarchical locality information from the IMDS. Additionally, as described below with reference to FIG. 10, the encoded hierarchical locality information can be unique per customer.

[0132] 10 illustrates an exemplary encoded array of hierarchical locality information for a host machine, according to certain embodiments. The encoded array of hierarchical locality information 1000 includes multiple blocks of hashed information, such as, for example, hash block 1 1010, hash block 2 1020, hash block 3 1030, and hash block 4 1040. It is understood that two consecutive hash blocks may be separated by an identifier 1015, which may correspond to a hyphen, semicolon, comma, or the like.

[0133] In one embodiment, hash block 1 1010 may include a hash of a rack identifier (i.e., the ID of the rack that contains the host machine) and a tenant ID (i.e., a customer ID). In that way, the encoded sequence is unique per customer. Specifically, including customer information (e.g., tenant ID) in the hash block may prevent two customers who happen to have host machines in the same rack from realizing that they are in the same rack. However, this allows a particular customer to know which instances of that customer are running on the same rack. In other words, the encoded sequence provides hierarchical locality information for a particular customer without revealing the placement of other customers. Similarly, hash block 1020 may include a hash of a block identifier and a tenant ID, while hash block 1030 may include a hash of a building identifier and a tenant ID, and hash block 1040 may include a hash of an availability domain identifier and a tenant ID.

[0134] In some embodiments, hierarchical locality information of host machines may be provided to cloud infrastructure customers. This allows customers to leverage the hierarchical locality information of host machines to provision workloads based on the type of application associated with the workload. For example, for workloads that require low latency, users can leverage the information contained in hash block 1 (1010), i.e., rack information, to select host machines on the same rack or adjacent racks. As another example, for GPU workloads, locality information can be used to configure bandwidth-efficient communication patterns (e.g., moving large amounts of data quickly). For applications that require high availability or applications that run on the front-end network side of a rack (see FIG. 7), users can leverage the information contained in one or more of the hash blocks (i.e., hash blocks 1010, 1020, 1030, and / or 1040 in FIG. 10) to select host machines that belong to, for example, different racks, blocks, or buildings to achieve a certain level of anti-affinity (i.e., high availability). It is understood that the hierarchical locality information of host machines may be utilized by applications, such as distributed Hadoop workloads and / or high-frequency trading applications (which require the selection of one or more host machines to support the application), in selecting one or more host machines to execute a desired task.

[0135] As another example, consider the case of a file system, network locality information can be leveraged to place clients close to the file system server to achieve low latency. Yet another application is a database application that consists of three tiers: a client tier, a mid-tier (e.g., application server tier), and a database tier. In such an application, a customer may desire low latency for the database workload. The customer can leverage network locality information to appropriately place clients, mid-tier servers, and databases to achieve low latency. In this scenario, it is understood that the customer can leverage network locality information to achieve high availability at the mid-tier and database tiers simultaneously.

[0136] FIG. 11A illustrates an exemplary flow chart showing steps performed in provisioning a request, according to certain embodiments. The process illustrated in FIG. 11 may be implemented in software (e.g., code, instructions, programs) executed by one or more processing units (e.g., processors, cores) of the respective system, hardware, or combination thereof. The software may be stored in a non-transitory storage medium (e.g., memory device). The method 1100 illustrated in FIG. 11 and described below is for illustrative purposes and not limiting. Although FIG. 11 illustrates various processing steps occurring in a particular sequence or order, this is not limiting. In certain alternative embodiments, steps may be performed in a different order and some steps may be performed in parallel.

[0137] The process begins at step 1105, where for each host machine of a plurality of host machines (i.e., host machines included in a cluster), hierarchical locality information of the host machine is stored. The hierarchical locality information of the host machine includes, for each locality of the plurality of localities, information identifying location information of the locality. In some embodiments, an instance metadata service may be utilized to store the hierarchical locality information in the host machine via a network virtualization device (NVD) associated with the host machine. It is noted that, as shown in FIG. 9, the hierarchical locality information may correspond to information indicating an identifier of a rack (i.e., rack ID) that includes the host machine, an identifier of a block that includes the rack, an identifier of a building that includes the block, and an identifier of a domain that includes the building.

[0138] At step 1110, the control plane receives a request (e.g., a request from a customer) to execute a workload. Note that in one embodiment, the workload corresponds to one or more processes executed using GPUs associated with a host machine. The process then moves to step 1115, where hierarchical locality information is obtained for each of a plurality of host machines. Note that the hierarchical locality information (for each host machine) may be stored by an instance metadata service of the corresponding host machine.

[0139] The process then proceeds to step 1120 where hierarchical locality information for the multiple host machines is provided in response to the request. According to some embodiments, once the customer has the hierarchical locality information for the multiple host machines, the customer may select one or more host machines for executing the workload. The selection of the one or more host machines is based on one or more constraints associated with the workload. More details regarding the constraints are provided below with reference to FIG. 11B. In step 1125, the control plane receives the selection of the one or more host machines. In step 1130, the process proceeds with executing the workload on the selected host machine or machines.

[0140] It is understood that the above steps of utilizing hierarchical locality information of host machines to execute a workload in no way limit the scope of the present disclosure. Rather, certain modifications to the steps are well within the scope of the present disclosure. For example, in one embodiment, as described next with reference to FIG. 11B, rather than the customer selecting the number of host machines on which to execute the workload, the control plane may select the number of host machines for the customer (i.e., based on one or more constraints associated with the customer's workload).

[0141] FIG. 11B illustrates another exemplary flow chart illustrating steps performed in provisioning a customer's workload request, according to certain embodiments. The process illustrated in FIG. 11 may be implemented in software (e.g., code, instructions, programs) executed by one or more processing units (e.g., processors, cores) of the respective system, hardware, or combination thereof. The software may be stored in a non-transitory storage medium (e.g., memory device). The method 1150 illustrated in FIG. 11 and described below is for illustrative purposes and not limiting. Although FIG. 11 illustrates various processing steps occurring in a particular sequence or order, this is not limiting. In certain alternative embodiments, steps may be performed in a different order and some steps may be performed in parallel.

[0142] The process begins at step 1155, where for each host machine of a plurality of host machines (i.e., host machines included in a cluster), hierarchical locality information of the host machine is stored. The hierarchical locality information of the host machine includes, for each locality of the plurality of localities, information identifying location information of the locality. In some embodiments, an instance metadata service may be utilized to store the hierarchical locality information in the host machine via a network virtualization device (NVD) associated with the host machine. It should be noted that, as shown in FIG. 9, the hierarchical locality information may correspond to information indicating an identifier of a rack (i.e., a rack ID) that includes the host machine, an identifier of a block that includes the rack, an identifier of a building that includes the block, and an identifier of a domain that includes the building.

[0143] At step 1160, a request is received from a customer. The request requests the number of host machines the customer desires to run the workload. It is understood that the request may include metadata corresponding to one or more constraints associated with the workload. In some embodiments, the one or more constraints may include a first constraint associated with a latency threshold, i.e., the customer may desire to run the workload such that the latency is below a certain threshold. A second constraint may correspond to an anti-affinity constraint. Such a constraint corresponds to a customer's desire to ensure some degree of availability of host machines. That is, at least some of the host machines selected to run the workload should be located in different racks. Such constraints are typically incorporated by the customer to address rack failure issues.

[0144] In step 1165, one or more constraints are extracted from the requests received in step 1160. Thereafter, the process moves to step 1170, where the control plane allocates one or more host machines (from multiple host machines) to execute the customer's workload. It is understood that the host machines allocated to execute the workload can be determined according to one or more constraints identified in step 1115 and / or the hierarchical locality information of the host machines. According to some embodiments, the process of step 1170 allocates host machines to execute the workload according to the topology of the network cluster (for example, the number of host machines included in a rack, the number of racks available in the system). Consider that each rack contains a total of N host machines and the number of host machines requested by the user is K. If K is less than N (i.e., K < N), in one implementation, all K host machines can be allocated from one rack. That is, all K host machines can be placed behind one TOR switch. Note that such an allocation minimizes latency. However, the user may also desire to achieve a certain level of anti-affinity, that is, availability. In that case, since some of the host machines allocated to the user can be selected from other racks of the network cluster, it is understood that such an allocation can be provided pending the user's approval. As another example, it can handle the case where K is greater than N (K > N). That is, the number of host machines requested by the user is more than the number of host machines included in a rack. In this case, in one implementation, the allocation can be performed so that the minimum number of TOR switches is used, that is, the in-rack routing is minimized. Thereafter, the process moves to step 1175, where the hierarchical locality information of the allocated host machines is provided to the customer. The process moves to step 1180, and the customer's workload is executed on one or more host machines allocated to the customer.

[0145] Example of an embodiment of a cloud infrastructure As mentioned above, infrastructure as a service (IaaS) is a specific type of cloud computing. IaaS can be configured to provide virtualized computing resources over a public network (e.g., the Internet). In the IaaS model, a cloud computing provider can host the infrastructure components (e.g., servers, storage devices, network nodes (e.g., hardware), deployment software, platform virtualization (e.g., hypervisor layer), etc.). In some cases, an IaaS provider can also provide various services (e.g., billing, monitoring, logging, security, load balancing, clustering, etc.) that accompany these infrastructure components. Accordingly, these services can be policy-driven, so that IaaS users may be able to implement policies that drive load balancing to maintain application availability and performance.

[0146] In some cases, IaaS customers can access resources and services over a wide area network (WAN) such as the Internet and use the cloud provider's services to install the remaining elements of their application stack. For example, a user can log into an IaaS platform to create virtual machines (VMs), install an operating system (OS) on each VM, deploy middleware such as databases, create storage buckets for workloads and backups, and even install enterprise software on the VMs. The customer can then use the provider's services to perform a variety of functions, such as distributing network traffic, troubleshooting application issues, monitoring performance, and managing disaster recovery.

[0147] In most cases, the cloud computing model requires the participation of a cloud provider, which may be, but does not have to be, a third-party service that specializes in providing (e.g., providing, renting, selling) IaaS. An entity may also choose to deploy a private cloud and become a provider of its own infrastructure services.

[0148] In some examples, IaaS deployment is the process of placing a new application, or a new version of an application, onto a prepared application server, etc. It may also include the server preparation process (e.g., installing libraries, daemons, etc.). This is often managed by the cloud provider below the hypervisor layer (e.g., server, storage, network hardware, virtualization). Thus, the customer may be responsible for handling the (OS), middleware, and / or application deployment (e.g., self-service virtual machines that can be started on demand).

[0149] In some examples, IaaS provisioning may refer to obtaining computers or virtual hosts for use and installing the necessary libraries or services on them. In most cases, deployment does not include provisioning, and provisioning may need to be performed first.

[0150] In some cases, there are two distinct challenges with IaaS provisioning. First, there is the initial challenge of provisioning the initial set of infrastructure before anything can be done. Second, there is the challenge of evolving the existing infrastructure after everything has been provisioned (e.g. adding new services, modifying services, removing services, etc.). In some cases, these two challenges can be addressed by allowing the configuration of the infrastructure to be defined declaratively. That is, the infrastructure (e.g. what components are needed and how they interact) can be defined by one or more configuration files. Thus, the overall topology of the infrastructure (e.g. which resources depend on which resources and how each of them work together) can be described declaratively. In some cases, once the topology is defined, workflows can be generated that create and / or manage the various components described in the configuration files.

[0151] In some examples, the infrastructure may have many interconnected elements. For example, there may be one or more virtual private clouds (VPCs) (e.g., a pool of potential on-demand configurable and / or shared computing resources), also known as a core network. In some examples, there may also be one or more security group rules that are provisioned to define how the security of the network and one or more virtual machines (VMs) are configured. Other infrastructure elements such as load balancers, databases, etc. may also be provisioned. The infrastructure may evolve in stages as more infrastructure elements are desired and / or added.

[0152] In some cases, continuous deployment techniques can be used to enable deployment of infrastructure code across different virtual computing environments. Additionally, the described techniques can enable infrastructure management within these environments. In some examples, a service team can create code that needs to be deployed to one or more, and often many, different production environments (e.g., different geographic locations, possibly across the globe). However, in some examples, the infrastructure onto which the code will be deployed must first be set up. In some cases, provisioning can be performed manually, resources can be provisioned using provisioning tools, and / or the code can be deployed using deployment tools once the infrastructure has been provisioned.

[0153] FIG. 12 is a block diagram 1200 illustrating an example pattern of an IaaS architecture according to at least one embodiment. A service operator 1202 can be communicatively coupled to a secure host tenant 1204, which can include a virtual cloud network (VCN) 1206 and a secure host subnet 1208. In some examples, the service operator 1202 can use one or more client computing devices. These devices can be portable handheld devices (e.g., iPhone, mobile phone, iPad, computing tablet, personal digital assistant (PDA)) or wearable devices (e.g., Google Glass head-mounted display), running software such as Microsoft Windows Mobile, and / or various mobile operating systems such as iOS, Windows Phone, Android, BlackBerry 8, Palm OS, and are Internet, email, short message service (SMS), BlackBerry, or other communication protocol enabled. Alternatively, the client computing devices can be general purpose personal computers including, for example, personal and / or laptop computers running various versions of Microsoft Windows, Apple Macintosh, and / or Linux operating systems. The client computing devices can be workstation computers running any of the various commercially available UNIX or UNIX-like operating systems (including, but not limited to, the various CNU / Linux operating systems such as Google Chrome OS).Alternatively, or in addition, the client computing devices may be other electronic devices capable of communicating over a network with access to the VCN 1206 and / or the Internet, such as thin-client computers, Internet-enabled gaming systems (e.g., Microsoft Xbox game consoles with or without Kinect® gesture input devices), and / or personal messaging devices.

[0154] VCN 1206 can include a local peering gateway (LPG) 1210 that can be communicatively coupled to a secure shell (SSH) VCN 1212 via an LPG 1210 that is included in SSH VCN 1212. SSH VCN 1212 can include an SSH subnet 1214, which can be communicatively coupled to a control plane VCN 1216 via an LPG 1210 that is included in control plane VCN 1216. SSH VCN 1212 can also be communicatively coupled to a data plane VCN 1218 via LPG 1210. The control plane VCN 1216 and the data plane VCN 1218 can be included in a service tenant 1219, which can be owned and / or operated by the IaaS provider.

[0155] The control plane VCN 1216 may include a control plane demilitarized zone (DMZ) tier 1220 that may function as a perimeter network (e.g., a portion of an enterprise network between the enterprise intranet and an external network). DMZ-based servers have limited scope of responsibility and may help limit security breaches. Additionally, the DMZ tier 1220 may include one or more load balancer (LB) subnets 1222, a control plane app tier 1224 that may include app subnets 1226, and a control plane data tier 1228 that may include database (DB) subnets 1230 (e.g., a front-end DB subnet and / or a back-end DB subnet). LB subnet 1222 included in control plane DMZ tier 1220 can be communicatively coupled to app subnet 1226 included in control plane app tier 1224 and Internet gateway 1234 that may be included in control plane VCN 1216, and app subnet 1226 can be communicatively coupled to DB subnet 1230 and service gateway 1236 and network address translation (NAT) gateway 1238 included in control plane data tier 1228. Control plane VCN 1216 can include service gateway 1236 and NAT gateway 1238.

[0156] The control plane VCN 1216 can include a data plane mirrored app layer 1240, which can include an app subnet 1226. The app subnet 1226 included in the data plane mirrored app layer 1240 can include a virtual network interface controller (VNIC) 1242 on which a compute instance 1244 can run. The compute instance 1244 can communicatively couple the app subnet 1226 of the data plane mirrored app layer 1240 to the app subnet 1226, which can be included in the data plane app layer 1246.

[0157] The data plane VCN 1218 may include a data plane app layer 1246, a data plane DMZ layer 1248, and a data plane data layer 1250. The data plane DMZ layer 1248 may include a LB subnet 1222 that may be communicatively coupled to an app subnet 1226 of the data plane app layer 1246 and an Internet gateway 1234 of the data plane VCN 1218. The app subnet 1226 may be communicatively coupled to a service gateway 1236 of the data plane VCN 1218 and a NAT gateway 1238 of the data plane VCN 1218. The data plane data layer 1250 may also include a DB subnet 1230 that may be communicatively coupled to the app subnet 1226 of the data plane app layer 1246.

[0158] The Internet gateways 1234 of the control plane VCNs 1216 and data plane VCNs 1218 can be communicatively coupled to a metadata management service 1252, which can be communicatively coupled to the public Internet 1254. The public Internet 1254 can be communicatively coupled to a NAT gateway 1238 of the control plane VCNs 1216 and data plane VCNs 1218. The service gateways 1236 of the control plane VCNs 1216 and data plane VCNs 1218 can be communicatively coupled to cloud services 1256.

[0159] In some examples, a service gateway 1236 in the control plane VCN 1216 or the data plane VCN 1218 can make application programming interface (API) calls to cloud services 1256 without traversing the public Internet 1254. API calls from the service gateway 1236 to the cloud services 1256 can be one-way; that is, the service gateway 1236 can make an API call to the cloud services 1256, and the cloud services 1256 can send the requested data to the service gateway 1236. However, the cloud services 1256 may not be able to initiate an API call to the service gateway 1236.

[0160] In some examples, the secure host tenant 1204 can be directly connected to a service tenant 1219 that may otherwise be isolated. The secure host subnet 1208 can communicate with the SSH subnet 1214 through the LPG 1210. The LPG 1210 allows bidirectional communication on an isolated system. Connecting the secure host subnet 1208 to the SSH subnet 1214 allows the secure host subnet 1208 to access other entities in the service tenant 1219.

[0161] The control plane VCN 1216 allows users of the service tenant 1219 to configure or provision desired resources. The required resources provisioned in the control plane VCN 1216 can be deployed or used in the data plane VCN 1218. In some examples, the control plane VCN 1216 can be separated from the data plane VCN 1218, and the data plane mirror app layer 1240 of the control plane VCN 1216 can communicate with the data plane app layer 1246 of the data plane VCN 1218 via a VNIC 1242, which can be included in the data plane mirror app layer 1240 and the data plane app layer 1246.

[0162] In some examples, a user, or customer, of the system can make a request, such as a create, read, update, or delete (CRUD) operation, via the public internet 1254, which can communicate the request to the metadata management service 1252. The metadata management service 1252 can communicate the request to the control plane VCN 1216 via the internet gateway 1234. The request can be received by the LB subnet 1222 included in the control plane DMZ layer 1220. The LB subnet 1222 can determine that the request is valid and, in response to this determination, can send the request to the app subnet 1226 included in the control plane app layer 1224. If the request is validated and a call to the public internet 1254 is required, the call to the public internet 1254 can be sent to the NAT gateway 1238, which can make the call to the public internet 1254. Any memory that may be desired to be stored by the request can be stored in the DB subnet 1230.

[0163] In some examples, the data plane mirror app layer 1240 can facilitate direct communication between the control plane VCN 1216 and the data plane VCN 1218. For example, it may be desired to apply a configuration change, update, or other appropriate modification to resources included in the data plane VCN 1218. The control plane VCN 1216 communicates directly with the resources included in the data plane VCN 1218 via the VNIC 1242, thereby enabling the configuration change, update, or other appropriate modification to be performed.

[0164] In some embodiments, the control plane VCN 1216 and the data plane VCN 1218 can be included within the service tenant 1219. In this case, a user or customer of the system cannot own or operate either the control plane VCN 1216 or the data plane VCN 1218. Instead, an IaaS provider can own or operate the control plane VCN 1216 and the data plane VCN 1218, both of which can be included in the service tenant 1219. This embodiment can allow for network isolation that may prevent a user or customer from interacting with the resources of other users or other customers. This embodiment also allows a user or customer of the system to store databases privately without relying on the public Internet 1254 for storage, which may not have the desired level of security.

[0165] In another embodiment, the LB subnet 1222 included in the control plane VCN 1216 can be configured to receive signals from the service gateway 1236. In this embodiment, the control plane VCN 1216 and the data plane VCN 1218 can be configured to be called by the IaaS provider's customers without calling the public Internet 1254. The IaaS provider's customers may desire this embodiment because databases used by the customers may be stored in the service tenant 1219, which may be controlled by the IaaS provider and isolated from the public Internet 1254.

[0166] 13 is a block diagram 1300 illustrating another example pattern of an IaaS architecture, according to at least one embodiment. A service operator 1302 (e.g., service operator 1202 of FIG. 12) can be communicatively coupled to a secure host tenant 1304 (e.g., secure host tenant 1204 of FIG. 12), which can include a virtual cloud network (VCN) 1306 (e.g., VCN 1206 of FIG. 12) and a secure host subnet 1308 (e.g., secure host subnet 1208 of FIG. 12). The VCN 1306 can include a local peering gateway (LPG) 1310 (e.g., LPG 1210 of FIG. 12), which can be communicatively coupled to a secure shell (SSH) VCN 1312 (e.g., SSH VCN 1212 of FIG. 12) via an LPG 1310 included in the SSH VCN 1312. SSH VCN 1312 may include an SSH subnet 1314 (e.g., SSH subnet 1214 of FIG. 12), which can be communicatively coupled to a control plane VCN 1316 (e.g., control plane VCN 1216 of FIG. 12) via an LPG 1310 included in the control plane VCN 1316. The control plane VCN 1316 can be included in a service tenant 1319 (e.g., service tenant 1219 of FIG. 12), and the data plane VCN 1318 (e.g., data plane VCN 1218 of FIG. 12) can be included in a customer tenant 1321, which may be owned or operated by a user or customer of the system.

[0167] The control plane VCN 1316 may include a control plane DMZ tier 1320 (e.g., control plane DMZ tier 1220 of FIG. 12 ) that may include a LB subnet 1322 (e.g., LB subnet 1222 of FIG. 12 ), a control plane app tier 1324 (e.g., control plane app tier 1224 of FIG. 12 ) that may include an app subnet 1326 (e.g., app subnet 1226 of FIG. 12 ), and a control plane data tier 1328 (e.g., control plane data tier 1228 of FIG. 12 ) that may include a database (DB) subnet 1330 (e.g., similar to DB subnet 1230 of FIG. 12 ). The LB subnet 1322 included in the control plane DMZ layer 1320 can be communicatively coupled to an app subnet 1326 included in the control plane app layer 1324 and an Internet gateway 1334 (e.g., Internet gateway 1234 in FIG. 12 ) that may be included in the control plane VCN 1316, and the app subnet 1326 can be communicatively coupled to a DB subnet 1330 and a service gateway 1336 (e.g., service gateway in FIG. 12 ) and a network address translation (NAT) gateway 1338 (e.g., NAT gateway 1238 in FIG. 12 ) included in the control plane data layer 1328. The control plane VCN 1316 can include the service gateway 1336 and the NAT gateway 1338.

[0168] The control plane VCN 1316 can include a data plane mirror app layer 1340 (e.g., data plane mirror app layer 1240 of FIG. 12 ), which can include an app subnet 1326. The app subnet 1326 included in the data plane mirror app layer 1340 can include a virtual network interface controller (VNIC) 1342 (e.g., VNIC 1242 ) on which a compute instance 1344 (e.g., similar to compute instance 1244 of FIG. 12 ) can run. The compute instance 1344 can facilitate communication between the app subnet 1326 of the data plane mirror app layer 1340 and the app subnet 1326 that can be included in the data plane app layer 1346 (e.g., data plane app layer 1246 of FIG. 12 ) via the VNIC 1342 included in the data plane mirror app layer 1340 and the VNIC 1342 included in the data plane app layer 1346.

[0169] The Internet gateway 1334 included in the control plane VCN 1316 can be communicatively coupled to a metadata management service 1352 (e.g., metadata management service 1252 of FIG. 12), which can be communicatively coupled to a public Internet 1354 (e.g., public Internet 1254 of FIG. 12). The public Internet 1354 can be communicatively coupled to a NAT gateway 1338 included in the control plane VCN 1316. The service gateway 1336 included in the control plane VCN 1316 can be communicatively coupled to cloud services 1356 (e.g., cloud services 1256 of FIG. 12).

[0170] In some examples, the data plane VCN 1318 can be included in the customer tenant 1321. In this case, the IaaS provider can provide each customer with a control plane VCN 1316, and the IaaS provider can configure a unique compute instance 1344 included in the service tenant 1319 for each customer. Each compute instance 1344 can enable communication between the control plane VCN 1316 included in the service tenant 1319 and the data plane VCN 1318 included in the customer tenant 1321. The compute instance 1344 enables resources provisioned in the control plane VCN 1316 included in the service tenant 1319 to be deployed or otherwise used in the data plane VCN 1318 included in the customer tenant 1321.

[0171] In another example, an IaaS provider customer may have a database that resides in customer tenant 1321. In this example, control plane VCN 1316 may include data plane mirror app tier 1340, which may include app subnet 1326. Data plane mirror app tier 1340 may reside in data plane VCN 1318, but data plane mirror app tier 1340 may not reside in data plane VCN 1318. That is, data plane mirror app tier 1340 may have access to customer tenant 1321, but data plane mirror app tier 1340 may not reside in data plane VCN 1318 or may not be owned or operated by the IaaS provider customer. Data plane mirror app tier 1340 may be configured to make calls to data plane VCN 1318, but may not be configured to make calls to entities contained in control plane VCN 1316. A customer may desire to deploy or otherwise use resources provisioned in the control plane VCN 1316 in the data plane VCN 1318, and the data plane mirror app layer 1340 can facilitate the customer's desired deployment or other use of the resources.

[0172] In some embodiments, the IaaS provider's customer can apply filters to the data plane VCN 1318. In this embodiment, the customer can determine what the data plane VCN 1318 can access, and the customer can limit access from the data plane VCN 1318 to the public Internet 1354. The IaaS provider may not be able to apply filters or control access from the data plane VCN 1318 to external networks and databases. Applying customer filters and controls to the data plane VCN 1318 contained in the customer tenant 1321 can help isolate the data plane VCN 1318 from other customers and the public Internet 1354.

[0173] In some embodiments, cloud services 1356 may be called by service gateway 1336 to access services that may not be in the public internet 1354, control plane VCN 1316, or data plane VCN 1318. The connection between cloud services 1356 and control plane VCN 1316 or data plane VCN 1318 may not exist or be continuous. Cloud services 1356 may be on a separate network owned or operated by the IaaS provider. Cloud services 1356 may be configured to receive calls from service gateway 1336 and not receive calls from the public internet 1354. Some cloud services 1356 may be isolated from other cloud services 1356, and control plane VCN 1316 may be isolated from cloud services 1356 that may not be in the same region as control plane VCN 1316. For example, control plane VCN 1316 may be located in “Region 1” and cloud service “Deployment 12” may be located in Region 1 and Region 2. If a call is made to a deployment 12 by a service gateway 1336 included in a control plane VCN 1316 in region 1, the call may be sent to the deployment 12 in region 1. In this example, the control plane VCN 1316, and thus the deployment 12 in region 1, may not be communicatively coupled or in communication with the deployment 12 in region 2.

[0174] 14 is a block diagram 1400 illustrating another example pattern of an IaaS architecture, according to at least one embodiment. A service operator 1402 (e.g., service operator 1202 of FIG. 12) can be communicatively coupled to a secure host tenant 1404 (e.g., secure host tenant 1204 of FIG. 12), which can include a virtual cloud network (VCN) 1406 (e.g., VCN 1206 of FIG. 12) and a secure host subnet 1408 (e.g., secure host subnet 1208 of FIG. 12). The VCN 1406 can include an LPG 1410 (e.g., LPG 1210 of FIG. 12), which can be communicatively coupled to an SSH VCN 1412 (e.g., SSH VCN 1212 of FIG. 12) via an LPG 1410 included in the SSH VCN 1412. SSH VCN 1412 may include an SSH subnet 1414 (e.g., SSH subnet 1214 of FIG. 12), which may be communicatively coupled to a control plane VCN 1416 via an LPG 1410 included in the control plane VCN 1416 (e.g., control plane VCN 1216 of FIG. 12) and to a data plane VCN 1418 via an LPG 1410 included in the data plane VCN 1418 (e.g., data plane 1218 of FIG. 12). The control plane VCN 1416 and the data plane VCN 1418 may be included in a service tenant 1419 (e.g., service tenant 1219 of FIG. 12).

[0175] The control plane VCN 1416 may include a control plane DMZ tier 1420 (e.g., control plane DMZ tier 1220 of FIG. 12 ) that may include a load balancer (LB) subnet 1422 (e.g., LB subnet 1222 of FIG. 12 ), a control plane app tier 1424 (e.g., control plane app tier 1224 of FIG. 12 ) that may include an app subnet 1426 (similar to app subnet 1226 of FIG. 12 ), and a control plane data tier 1428 (e.g., control plane data tier 1228 of FIG. 12 ) that may include a DB subnet 1430. The LB subnet 1422 included in the control plane DMZ layer 1420 can be communicatively coupled to an app subnet 1426 included in the control plane app layer 1424 and an Internet gateway 1434 (e.g., Internet gateway 1234 in FIG. 12 ) that may be included in the control plane VCN 1416, and the app subnet 1426 can be communicatively coupled to a DB subnet 1430 and a service gateway 1436 (e.g., service gateway in FIG. 12 ) and a network address translation (NAT) gateway 1438 (e.g., NAT gateway 1238 in FIG. 12 ) included in the control plane data layer 1428. The control plane VCN 1416 can include the service gateway 1436 and the NAT gateway 1438.

[0176] The data plane VCN 1418 can include a data plane app layer 1446 (e.g., data plane app layer 1246 of FIG. 12), a data plane DMZ layer 1448 (e.g., data plane DMZ layer 1248 of FIG. 12), and a data plane data layer 1450 (e.g., data plane data layer 1250 of FIG. 12). The data plane DMZ layer 1448 can include a trusted app subnet 1460 and an untrusted app subnet 1462 of the data plane app layer 1446, and a LB subnet 1422 that can be communicatively coupled to an Internet gateway 1434 included in the data plane VCN 1418. The trusted app subnet 1460 can be communicatively coupled to a service gateway 1436 included in the data plane VCN 1418, a NAT gateway 1438 included in the data plane VCN 1418, and a DB subnet 1430 included in the data plane data layer 1450. The untrusted app subnet 1462 can be communicatively coupled to a service gateway 1436 included in the data plane VCN 1418 and a DB subnet 1430 included in the data plane data layer 1450. The data plane data layer 1450 can include a DB subnet 1430 that can be communicatively coupled to a service gateway 1436 included in the data plane VCN 1418.

[0177] The untrusted app subnet 1462 may include one or more primary VNICs 1464(1)-(N) that may be communicatively coupled to tenant virtual machine (VM)1 466(1)-(N). Each tenant VM1 466(1)-(N) may be communicatively coupled to a respective app subnet 1467(1)-(N) that may be included in a respective container egress VCN 1468(1)-(N) that may be included in a respective customer tenant 1470(1)-(N). Each secondary VNIC 1472(1)-(N) may facilitate communication between the untrusted app subnet 1462 included in the data plane VCN 1418 and the app subnet included in the container egress VCN 1468(1)-(N). Each container egress VCN 1468(1)-(N) may include a NAT gateway 1438 that may be communicatively coupled to the public internet 1454 (e.g., public internet 1254 in FIG. 12).

[0178] An Internet gateway 1434 included in the control plane VCN 1416 and included in the data plane VCN 1418 can be communicatively coupled to a metadata management service 1452 (e.g., metadata management system 1252 of FIG. 12 ), which can be communicatively coupled to the public Internet 1454. The public Internet 1454 can be communicatively coupled to a NAT gateway 1438 included in the control plane VCN 1416 and included in the data plane VCN 1418. A service gateway 1436 included in the control plane VCN 1416 and included in the data plane VCN 1418 can be communicatively coupled to cloud services 1456.

[0179] In some embodiments, the data plane VCN 1418 can be integrated with a customer tenant 1470. This integration can be useful or desirable for an IaaS provider's customer in some cases, such as when support is desired in running code. A customer may provide code to be executed that may be disruptive, communicate with other customer resources, or cause other undesirable effects. In response, the IaaS provider can decide whether to run code provided by the customer to the IaaS provider.

[0180] In some examples, an IaaS provider's customer may request the IaaS provider grant temporary network access to the ability to connect to data plane layer apps 1446. Code to perform the functions may be executed in VM1 466(1)-(N), and the code may not be configured to run elsewhere on the data plane VCN 1418. Each VM1 466(1)-(N) may be connected to one customer tenant 1470. Each container 1471(1)-(N) contained in VM1 466(1)-(N) may be configured to execute code. In this case, there may be double isolation (e.g., container 1471(1)-(N) executes code, and container 1471(1)-(N) may be contained in VM1 466(1)-(N) that is at least in untrusted app subnet 1462), which may help prevent erroneous or unwanted code from damaging the IaaS provider's network or damaging another customer's network. Containers 1471(1)-(N) may be communicatively coupled to customer tenants 1470 and configured to send or receive data from customer tenants 1470. Containers 1471(1)-(N) may not be configured to send or receive data from other entities in data plane VCN 1418. Once code execution is complete, the IaaS provider may kill or otherwise dispose of containers 1471(1)-(N).

[0181] In some embodiments, trusted app subnet 1460 may execute code that may be owned or operated by the IaaS provider. In this embodiment, trusted app subnet 1460 may be communicatively coupled to DB subnet 1430 and configured to perform CRUD operations on DB subnet 1430. Untrusted app subnet 1462 may be communicatively coupled to DB subnet 1430, but in this embodiment, untrusted app subnet 1462 may be configured to perform read operations on DB subnet 1430. Containers 1471(1)-(N) included in each customer's VM1 466(1)-(N) and that may execute code from the customer may not be communicatively coupled to DB subnet 1430.

[0182] In other embodiments, the control plane VCN 1416 and the data plane VCN 1418 may not be directly communicatively coupled. In this embodiment, there may be no direct communication between the control plane VCN 1416 and the data plane VCN 1418. However, communication may occur indirectly through at least one method. An IaaS provider may establish an LPG 1410 that can facilitate communication between the control plane VCN 1416 and the data plane VCN 1418. In another example, the control plane VCN 1416 or the data plane VCN 1418 can call a cloud service 1456 through a service gateway 1436. For example, a call from the control plane VCN 1416 to the cloud service 1456 may include a request for a service that can communicate with the data plane VCN 1418.

[0183] 15 is a block diagram 1500 illustrating another example pattern of an IaaS architecture, according to at least one embodiment. A service operator 1502 (e.g., service operator 1202 of FIG. 12) can be communicatively coupled to a secure host tenant 1504 (e.g., secure host tenant 1204 of FIG. 12), which can include a virtual cloud network (VCN) 1506 (e.g., VCN 1206 of FIG. 12) and a secure host subnet 1508 (e.g., secure host subnet 1208 of FIG. 12). The VCN 1506 can include an LPG 1510 (e.g., LPG 1210 of FIG. 12), which can be communicatively coupled to an SSH VCN 1512 (e.g., SSH VCN 1212 of FIG. 12) via an LPG 1510 included in the SSH VCN 1512. SSH VCN 1512 may include an SSH subnet 1514 (e.g., SSH subnet 1214 of FIG. 12), which may be communicatively coupled to a control plane VCN 1516 via an LPG 1510 included in the control plane VCN 1516 (e.g., control plane VCN 1216 of FIG. 12) and to a data plane VCN 1518 via an LPG 1510 included in the data plane VCN 1518 (e.g., data plane 1218 of FIG. 12). The control plane VCN 1516 and the data plane VCN 1518 may be included in a service tenant 1519 (e.g., service tenant 1219 of FIG. 12).

[0184] The control plane VCN 1516 may include a control plane DMZ layer 1520 (e.g., control plane DMZ layer 1220 of FIG. 12) that may include a LB subnet 1522 (e.g., LB subnet 1222 of FIG. 12), a control plane app layer 1524 (e.g., control plane app layer 1224 of FIG. 12) that may include an app subnet 1526 (e.g., app subnet 1226 of FIG. 12), and a control plane data layer 1528 (e.g., control plane data layer 1228 of FIG. 12) that may include a DB subnet 1530 (e.g., DB subnet 1430 of FIG. 14). The LB subnet 1522 included in the control plane DMZ layer 1520 can be communicatively coupled to an app subnet 1526 included in the control plane app layer 1524 and an Internet gateway 1534 (e.g., Internet gateway 1234 in FIG. 12 ) that may be included in the control plane VCN 1516, and the app subnet 1526 can be communicatively coupled to a DB subnet 1530 and a service gateway 1536 (e.g., service gateway in FIG. 12 ) and a network address translation (NAT) gateway 1538 (e.g., NAT gateway 1238 in FIG. 12 ) included in the control plane data layer 1528. The control plane VCN 1516 can include the service gateway 1536 and the NAT gateway 1538.

[0185] The data plane VCN 1518 can include a data plane app layer 1546 (e.g., data plane app layer 1246 of FIG. 12), a data plane DMZ layer 1548 (e.g., data plane DMZ layer 1248 of FIG. 12), and a data plane data layer 1550 (e.g., data plane data layer 1250 of FIG. 12). The data plane DMZ layer 1548 can include a trusted app subnet 1560 (e.g., trusted app subnet 1460 of FIG. 14) and an untrusted app subnet 1562 (e.g., untrusted app subnet 1462 of FIG. 14) of the data plane app layer 1546, and a LB subnet 1522 that can be communicatively coupled to an Internet gateway 1534 included in the data plane VCN 1518. The trusted app subnet 1560 can be communicatively coupled to a service gateway 1536 included in the data plane VCN 1518, a NAT gateway 1538 included in the data plane VCN 1518, and a DB subnet 1530 included in the data plane data layer 1550. The untrusted app subnet 1562 can be communicatively coupled to a service gateway 1536 included in the data plane VCN 1518 and a DB subnet 1530 included in the data plane data layer 1550. The data plane data layer 1550 can include a DB subnet 1530 that can be communicatively coupled to a service gateway 1536 included in the data plane VCN 1518.

[0186] The untrusted app subnet 1562 can include primary VNICs 1564(1)-(N) that can be communicatively coupled to tenant virtual machines (VMs) 1 566(1)-(N) that reside in the untrusted app subnet 1562. Each tenant VM 1 566(1)-(N) executes code within a respective container 1567(1)-(N) and is communicatively coupled to an app subnet 1526 that can be included within a data plane app tier 1546 that can be included within a container egress VCN 1568. Each secondary VNIC 1572(1)-(N) can facilitate communication between the untrusted app subnet 1562 included in the data plane VCN 1518 and the app subnet included in the container egress VCN 1568. The container egress VCN can include a NAT gateway 1538 that can be communicatively coupled to the public internet 1554 (e.g., public internet 1254 in FIG. 12).

[0187] An Internet gateway 1534 included in the control plane VCN 1516 and in the data plane VCN 1518 can be communicatively coupled to a metadata management service 1552 (e.g., metadata management system 1252 of FIG. 12 ), which can be communicatively coupled to the public Internet 1554. The public Internet 1554 can be communicatively coupled to a NAT gateway 1538 included in the control plane VCN 1516 and in the data plane VCN 1518. A service gateway 1536 included in the control plane VCN 1516 and in the data plane VCN 1518 can be communicatively coupled to cloud services 1556.

[0188] In some examples, the pattern illustrated by the architecture of block diagram 1500 of FIG. 15 may be considered an exception to the pattern illustrated by the architecture of block diagram 1400 of FIG. 14 and may be desirable for an IaaS provider's customer when the IaaS provider cannot communicate directly with the customer (e.g., in a disconnected region). Each container 1567(1)-(N) included in each customer's VM1 566(1)-(N) can be accessed by the customer in real time. The containers 1567(1)-(N) can be configured to call a respective secondary VNIC 1572(1)-(N) included in the app subnet 1526 of the data plane app tier 1546 that can be included in the container egress VCN 1568. The secondary VNIC 1572(1)-(N) can send the call to a NAT gateway 1538, which can send the call to the public Internet 1554. In this example, containers 1567(1)-(N) that a customer can access in real time can be isolated from control plane VCN 1516 and can be isolated from other entities included in data plane VCN 1518. Containers 1567(1)-(N) can also be isolated from resources of other customers.

[0189] In another example, a customer can call cloud service 1556 using container 1567(1)-(N). In this example, the customer can execute code within container 1567(1)-(N) that requests a service from cloud service 1556. Container 1567(1)-(N) can send the request to secondary VNIC 1572(1)-(N), which can send the request to a NAT gateway, which can send the request to public internet 1554. Public internet 1554 can send the request to LB subnet 1522, which is included in control plane VCN 1516, via internet gateway 1534. If the request is determined to be valid, the LB subnet can send the request to app subnet 1526, which can send the request to cloud service 1556 via service gateway 1536.

[0190] It should be noted that the IaaS architectures 1200, 1300, 1400, 1500 depicted in the figures may have components other than those depicted. Additionally, the embodiments depicted in the figures are only some examples of cloud infrastructure systems that may incorporate embodiments of the present disclosure. In some other embodiments, the IaaS systems may have more or fewer components than depicted in the figures, may combine two or more components, or may have different configurations or arrangements of components.

[0191] In certain embodiments, the IaaS systems described herein may include a suite of application, middleware, and database service offerings that are delivered to customers in a self-service, subscription-based, elastically scalable, reliable, highly available, and secure manner. One example of such an IaaS system is Oracle Cloud Infrastructure (OCI), offered by the present assignee.

[0192] 16 illustrates an exemplary computer system 1600 in which various embodiments may be implemented. System 1600 may be used to implement any of the computer systems described above. As shown, computer system 1600 includes a processing unit 1604 that communicates with a number of peripheral subsystems via a bus subsystem 1602. These peripheral subsystems may include a processing accelerator 1606, an I / O subsystem 1608, a storage subsystem 1618, and a communication subsystem 1624. The storage subsystem 1618 includes a tangible computer readable storage medium 1622 and a system memory 1610.

[0193] Bus subsystem 1602 provides mechanisms that allow the various components and subsystems of computer system 1600 to communicate with each other as intended. Although bus subsystem 1602 is shown diagrammatically as a single bus, alternative embodiments of the bus subsystem may utilize multiple buses. Bus subsystem 1602 may be any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. For example, such architectures may include an Industry Standard Architecture (ISA) bus, a MicroChannel Architecture (MCA) bus, an Enhanced ISA (EISA) bus, a Video Electronics Standards Association (VESA) local bus, and a Peripheral Component Interconnect (PCI) bus, which may be implemented as a mezzanine bus manufactured in accordance with the IEEE P1386.1 standard.

[0194] The processing unit 1604 may be implemented as one or more integrated circuits (e.g., conventional microprocessors or microcontrollers) and controls the operation of the computer system 1600. The processing unit 1604 may include one or more processors. These processors may include single-core processors or multi-core processors. In particular embodiments, the processing unit 1604 may be implemented as one or more independent processing units 1632 and / or 1634, with each processing unit including a single or multi-core processor. In other embodiments, the processing unit 1604 may be implemented as a quad-core processing unit formed by integrating two dual-core processors into one chip.

[0195] In various embodiments, the processing unit 1604 may execute various programs in response to program code and may maintain multiple simultaneously executing programs or processes. At any given time, some or all of the program code being executed may reside in the processor 1604 and / or in the memory subsystem 1618. With appropriate programming, the processor 1604 may provide the various functions described above. The computer system 1600 may further include a processing accelerator 1606, which may include a digital signal processor (DSP), special purpose processor, or the like.

[0196] The I / O subsystem 1608 may include user interface input devices and user interface output devices. User interface input devices may include keyboards, pointing devices such as mice or trackballs, touch pads or touch screens integrated into displays, scroll wheels, click wheels, dials, buttons, switches, keypads, audio input devices with voice command recognition systems, microphones, and other types of input devices. User interface input devices may include motion sensing devices and / or gesture recognizers, such as, for example, a Microsoft Kinect® motion sensor. The Microsoft Kinect® motion sensor allows users to control and interact with input devices, such as a Microsoft Xbox® 360 game controller, through a natural user interface using gestures and voice commands. User interface input devices may also include eye gesture recognizers, such as a Google Glass® blink detector, that detects the user's eye movements (e.g., "blinking" when taking a picture and / or selecting a menu) and translates the eye gestures as input to an input device (e.g., Google Glass®). Additionally, the user interface input devices may include voice recognition sensing devices that allow a user to interact with a voice recognition system (e.g., the Siri® navigator) through voice commands.

[0197] User interface input devices may also include, but are not limited to, three-dimensional (3D) mice, joysticks or pointing sticks, game pads and graphic tablets, as well as audio / visual devices such as speakers, digital cameras, digital video cameras, portable media players, webcams, image scanners, fingerprint scanners, barcode readers 3D scanners, 3D printers, laser range finders, eye-tracking devices, etc. Additionally, user interface input devices may include medical imaging input devices such as, for example, computed tomography, magnetic resonance imaging, position emission tomography, medical ultrasound devices, etc. User interface input devices may also include audio input devices such as, for example, MIDI keyboards, digital musical instruments, etc.

[0198] User interface output devices may include a display subsystem, indicator lights, or non-visual displays such as audio output devices. The display subsystem may be a cathode ray tube (CRT), a flat panel device using a liquid crystal display (LCD) or a plasma display, a projection device, a touch screen, etc. In general, use of the term "output device" is intended to include any type of device or mechanism for outputting information from computer system 1600 to a user or to another computer. For example, user interface output devices may include, but are not limited to, a variety of display devices that visually convey textual, graphical, or audio / video information, such as monitors, printers, speakers, headphones, automobile navigation systems, plotters, voice output devices, modems, etc.

[0199] Computer system 1600 can include a storage subsystem 1618 that includes software elements currently shown as located in system memory 1610. System memory 1610 can store program instructions that can be loaded and executed by processing unit 1604, as well as data generated during the execution of these programs.

[0200] Depending on the configuration and type of computer system 1600, the system memory 1610 may be volatile (e.g., random access memory (RAM)) and / or non-volatile (e.g., read only memory (ROM), flash memory, etc.). RAM typically contains data and / or program modules that are immediately accessible by or presently being operated on and executed by the processing unit 1604. In some implementations, the system memory 1610 may include a number of different types of memory, such as static random access memory (SRAM) and dynamic random access memory (DRAM). In some implementations, a basic input / output system (BIOS), containing the basic routines that help to transfer information between elements within the computer system 1600, such as during start-up, may typically be stored in ROM. By way of example and not limitation, the system memory 1610 also illustrates application programs 1612, program data 1614, and an operating system 1616, which may include client applications, a web browser, a mid-tier application, a relational database management system (RDBMS), etc. As an example, operating system 1616 may include various versions of Microsoft Windows®, Apple Macintosh®, and / or Linux operating systems, various commercially available UNIX® or UNIX-like operating systems (including, but not limited to, various GNU / Linux operating systems, Google Chrome® OS, etc.), and / or mobile operating systems such as iOS, Windows® Phone, Android® OS, BlackBerry® 16 OS, Palm® OS operating systems, etc.

[0201] The storage subsystem 1618 may also provide a tangible computer-readable storage medium for storing the basic programming and data constructs that provide the functionality of some embodiments. Software (programs, code modules, instructions) that, when executed by the processor, provide the above-described functionality may be stored in the storage subsystem 1618. These software modules or instructions may be executed by the processing unit 1604. The storage subsystem 1618 may also provide a repository for storing data used in accordance with the present disclosure.

[0202] The storage subsystem 1600 may also include a computer readable storage medium reader 1620 that may further be connected to a computer readable storage medium 1622. The computer readable storage medium 1622, together with and optionally in combination with the system memory 1610, may collectively represent storage media for containing, storing, transmitting, and retrieving computer readable information on a temporary and / or more permanent basis, in addition to remote, local, fixed, and / or removable storage devices. Non-transitory computer readable storage media may include physically tangible memory or storage devices, including volatile memory storage devices and / or non-volatile storage devices. Examples of non-transitory computer readable storage media include magnetic storage media (e.g., disks and tapes), optical storage media (e.g., DVDs, CDs), various types of RAM, ROM, or flash memory, hard drives, floppy drives, removable memory drives (e.g., USB drives), and other types of storage devices.

[0203] The computer readable storage medium 1622 containing the code or portions of code may include any suitable medium known or used in the art, including, but not limited to, storage media and communication media, such as volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing and / or transmitting information, which may include tangible computer readable storage media, such as RAM, ROM, Electronically Erasable Programmable ROM (EEPROM), flash memory or other memory technology, CD-ROM, Digital Versatile Disk (DVD) or other optical storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage, or other tangible computer readable medium.

[0204] As an example, the computer readable storage medium 1622 may include hard disk drives that read or write from non-removable non-volatile magnetic media, magnetic disk drives that read or write from removable non-volatile magnetic disks, and optical disk drives that read or write from removable non-volatile optical disks such as CD-ROMs, DVDs, Blu-Ray® disks, or other optical media. The computer readable storage medium 1622 may include, but is not limited to, Zip® drives, flash memory cards, Universal Serial Bus (USB) flash drives, Secure Digital (SD) cards, DVD disks, digital video tapes, and the like. The computer readable storage medium 1622 may also include solid state drives (SSDs) based on non-volatile memory such as flash memory-based SSDs, enterprise flash drives, solid state ROMs, SSDs based on volatile memory such as solid state RAM, dynamic RAM, static RAM, DRAM-based SSDs, magnetoresistive RAM (MRAM) SSDs, and hybrid SSDs that use a combination of DRAM and flash memory-based SSDs. The disk drives and their associated computer-readable media may provide non-volatile storage of computer-readable instructions, data structures, program modules, and other data for computer system 1600.

[0205] The communications subsystem 1624 provides an interface to other computer systems and networks. The communications subsystem 1624 serves as an interface for transmitting and receiving data from the computer system 1600 to and from other systems. For example, the communications subsystem 1624 allows the computer system 1600 to connect to one or more devices via the Internet. In some embodiments, the communications subsystem 1624 may include radio frequency (RF) transceiver components for accessing wireless voice and / or data networks (e.g., using cellular technology, advanced data network technologies such as 3G, 4G, EDGE (Enhanced Data Rates for Global Evolution), WiFi (IEEE 802.11 family standard, or other mobile communications technologies, or any combination thereof), Global Positioning System (GPS) receiver components, and / or other components). In some embodiments, the communications subsystem 1624 may provide a wired network connection (e.g., Ethernet) in addition to or instead of a wireless interface.

[0206] In some embodiments, the communications subsystem 1624 may also receive incoming communications in the form of structured and / or unstructured data feeds 1626, event streams 1628, event updates 1630, etc., on behalf of one or more users who may be using the computer system 1600.

[0207] As an example, the communications subsystem 1624 may be configured to receive data feeds 1626 in real time from users of social networks and / or other communications services, such as web feeds such as Twitter® feeds, Facebook® updates, Rich Site Summary (RSS) feeds, and / or real-time updates from one or more third party information sources.

[0208] Additionally, the communications subsystem 1624 may also be configured to receive data in the form of a continuous data stream. A continuous data stream may include an event stream 1628 of real-time events and / or event updates 1630 that may have no explicit end and may be continuous or unlimited in nature. Examples of applications that generate continuous data may include, for example, sensor data applications, financial tickers, network performance measurement tools (e.g., network monitoring and traffic management applications), clickstream analysis tools, automobile traffic monitoring, and the like.

[0209] The communications subsystem 1624 may also be configured to output structured and / or unstructured data feeds 1626, event streams 1628, event updates 1630, etc. to one or more databases that may be in communication with one or more streaming data source computers coupled to the computer system 1600.

[0210] The computer system 1600 may be any of a variety of types, including a handheld portable device (e.g., an iPhone® mobile phone, an iPad® computing tablet, a PDA), a wearable device (e.g., a Google Glass® head mounted display), a PC, a workstation, a mainframe, a kiosk, a server rack, or other data processing system.

[0211] Due to the ever-changing nature of computers and networks, the description of computer system 1600 shown in the figure is intended as a specific example only. Many other configurations are possible having more or fewer components than the system shown in the figure. For example, customized hardware may also be used, and / or particular elements may be implemented in hardware, firmware, software (including applets), or a combination thereof. Additionally, connections to other computing devices, such as network input / output devices, may also be used. Based on the disclosure and teachings provided herein, one of ordinary skill in the art will appreciate other ways and / or techniques for implementing various embodiments.

[0212] Although specific embodiments have been described, various modifications, variations, alternative configurations, and equivalents are within the scope of the disclosure. The embodiments are not limited to operating in a particular data processing environment, but can freely operate in multiple data processing environments. Furthermore, while the embodiments are described using a particular sequence of transactions and steps, it should be apparent to one skilled in the art that the scope of the disclosure is not limited to the sequence of transactions and steps described. Various features and aspects of the above-described embodiments can be used individually or in combination.

[0213] Additionally, while the embodiments are described using specific hardware and software combinations, it should be appreciated that other hardware and software combinations are within the scope of the present disclosure. The embodiments may be implemented using only hardware, only software, or a combination thereof. The various processes described herein may be implemented on any combination of the same or different processors. Thus, when a component or module is described as being configured to perform a particular operation, such configuration may be achieved, for example, by designing electronic circuitry to perform the operation, by programming a programmable electronic circuit (e.g., a microprocessor) to perform the operation, or any combination thereof. The processes may communicate using a variety of techniques, including, but not limited to, conventional techniques for inter-process communication, and different pairs of processes may use different techniques, or the same pair of processes may use different techniques at different times.

[0214] Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. It will be apparent, however, that additions, deductions, deletions, and other modifications and alterations are possible without departing from the broader spirit and scope as defined in the claims. Thus, although certain disclosed embodiments have been described, they are not intended to be limiting. Various modifications and equivalents are within the scope of the following claims.

[0215] Use of the terms "a" and "an" and "the" and similar referents in the context of describing the disclosed embodiments (particularly in the context of the claims below) shall be construed to include both the singular and the plural, unless otherwise stated herein or clearly contradicted by context. The terms "comprise", "have", "include", and "contain" shall be construed as open-ended terms (i.e., meaning "including, but not limited to"), unless otherwise stated. The term "connected" shall be construed as being partially or wholly contained within, connected to, or connected to, even if there is something intervening. The recitation of ranges of values ​​herein is intended to serve as a shorthand method of individually referring to each individual value falling within the range, unless otherwise stated herein, and each individual value is incorporated into the specification as if it were individually set forth herein. All methods described herein can be performed in any suitable order, unless otherwise stated herein or clearly contradicted by context. Any examples provided herein, or the use of exemplary language (e.g., "etc.") are intended only to more clearly illustrate the embodiments and do not limit the scope of the disclosure, unless specifically stated. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure.

[0216] Disjunctions such as the phrase "at least one of X, Y, or Z," unless otherwise noted, are generally intended to be understood within the context in which they are used to indicate that an item, term, etc. can be either X, Y, or Z, or any combination thereof (e.g., X, Y, and / or Z). Thus, such disjunctions are generally not intended to, and should not, imply that a particular embodiment requires that at least one of X, at least one of Y, or at least one of Z, respectively, be present.

[0217] Preferred embodiments of the present disclosure are described herein, including the best mode known for carrying out the present disclosure. Variations of these preferred embodiments will become apparent to those skilled in the art upon reading the foregoing description. Those skilled in the art will be able to adopt such variations as necessary, and the present disclosure may be carried out in other ways than as specifically described herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of all possible variations of the above-described elements is encompassed in the present disclosure, unless otherwise stated herein.

[0218] All references cited herein, including publications, patent applications, patents, are incorporated herein by reference to the same extent as if each reference was individually and specifically indicated to be incorporated by reference and was set forth in its entirety herein. In the foregoing specification, aspects of the disclosure have been described with reference to specific embodiments thereof, but those skilled in the art will understand that the disclosure is not limited thereto. Various features and aspects of the disclosure described above can be used individually or in combination. Moreover, the embodiments can be utilized in any number of environments and applications other than those described herein without departing from the broader spirit and scope of the specification. Thus, the specification and drawings should be regarded as illustrative and not restrictive.< / realm>

Claims

1. storing, for each host machine of a plurality of host machines, hierarchical locality information of the host machine, the hierarchical locality information of the host machines identifying location information of the host machine for each of a plurality of hierarchical levels; In response to receiving a request to run a workload, obtaining the hierarchical locality information for the plurality of host machines; providing said hierarchical locality information of said plurality of host machines in response to said request.

2. The method of claim 1 , wherein the multiple hierarchical levels include rack locality, block locality, building locality, and available domain locality.

3. The method of claim 2 , wherein the location information for each hierarchical level of the plurality of hierarchical levels includes an identifier for the hierarchical level.

4. 2. The method of claim 1, further comprising: generating an encoded array including the hierarchical locality information of the host machine, the encoded array including a plurality of hash blocks, each hash block including encoded location information of a particular locality.

5. 5. The method of claim 4, wherein the encoded array includes: (i) a first hash block containing a hash of a rack identifier for a rack that contains the host machine and a customer identifier; (ii) a second hash block containing a hash of a block identifier for a block that contains the rack and the customer identifier; (iii) a third hash block containing a hash of a building identifier for a building that contains the block and the customer identifier; and (iv) a fourth hash block containing a hash of a domain identifier for a domain that contains the building and the customer identifier.

6. a client receiving the hierarchical locality information for the plurality of host machines; selecting one or more host machines from the plurality of host machines for executing a workload, the selection being performed based on one or more constraints associated with the workload; The method of claim 1 , further comprising executing the workload on the one or more host machines.

7. 7. The method of claim 6, wherein the one or more constraints include a first constraint corresponding to a latency threshold associated with the workload and a second constraint associated with a desired degree of availability in executing the workload.

8. 2. The method of claim 1 , wherein the hierarchical locality information for the host machine is obtained from an instance metadata service, and the hierarchical locality information is stored on the host machine by the instance metadata service via a network virtualization appliance associated with the host machine.

9. A computer-readable medium storing computer-executable instructions that, when executed by one or more processors, storing, for each host machine of a plurality of host machines, hierarchical locality information of the host machine, the hierarchical locality information of the host machines identifying location information of the host machine for each of a plurality of hierarchical levels; The computer executable instructions include: In response to receiving a request to run a workload, obtaining the hierarchical locality information for the plurality of host machines; a computer readable medium causing, in response to said request, providing said hierarchical locality information of said plurality of host machines;

10. 10. The computer-readable medium storing computer-executable instructions of claim 9, wherein the plurality of hierarchical levels comprises rack locality, block locality, building locality, and available domain locality.

11. The computer-readable medium storing computer-executable instructions of claim 10 , wherein the location information for each hierarchical level of the plurality of hierarchical levels includes an identifier for the hierarchical level.

12. The instructions, when executed by one or more processors, 10. The computer-readable medium storing computer-executable instructions of claim 9, further comprising instructions for generating an encoded array including the hierarchical locality information of the host machine, the encoded array including a plurality of hash blocks, each hash block including encoded location information of a particular locality.

13. 13. The computer-readable medium storing computer-executable instructions of claim 12, wherein the encoded array includes: (i) a first hash block including a hash of a rack identifier for a rack that includes the host machine and a customer identifier; (ii) a second hash block including a hash of a block identifier for a block that includes the rack and the customer identifier; (iii) a third hash block including a hash of a building identifier for a building that includes the block and the customer identifier; and (iv) a fourth hash block including a hash of a domain identifier for a domain that includes the building and the customer identifier.

14. The instructions, when executed by one or more processors, receiving, by a client, the hierarchical locality information for the plurality of host machines; further comprising instructions for selecting one or more host machines from the plurality of host machines for executing a workload, the selection being performed based on one or more constraints associated with the workload; 10. The computer-readable medium storing computer-executable instructions of claim 9, further comprising instructions for causing execution of said workload on said one or more host machines.

15. 15. The computer-readable medium storing computer-executable instructions of claim 14, wherein the one or more constraints include a first constraint corresponding to a latency threshold associated with the workload and a second constraint associated with a desired degree of availability in executing the workload.

16. 10. The computer-readable medium storing computer-executable instructions of claim 9, wherein the hierarchical locality information for the host machine is obtained from an instance metadata service, and the hierarchical locality information is stored on the host machine by the instance metadata service via a network virtualization appliance associated with the host machine.

17. A processor; and a memory containing instructions, The instructions, when executed by the processor, cause the computing device to storing, for each host machine of a plurality of host machines, hierarchical locality information of the host machine, the hierarchical locality information of the host machines identifying location information of the host machine for each of a plurality of hierarchical levels; The instructions, when executed by the processor, cause the computing device to: In response to receiving a request to run a workload, obtaining the hierarchical locality information for the plurality of host machines; a computing device configured to provide said hierarchical locality information of said plurality of host machines in response to said request;

18. The computing device of claim 17 , wherein the plurality of hierarchical levels includes rack locality, block locality, building locality, and available domain locality.

19. The computing device of claim 17 , wherein the location information for each hierarchical level of the plurality of hierarchical levels includes an identifier for the hierarchical level.

20. 20. The computing device of claim 17, further configured to generate an encoded array including the hierarchical locality information of the host machine, the encoded array including a plurality of hash blocks, each hash block including encoded location information of a particular locality.

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