GSLB Site Persistence via Virtual Server Configuration
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Solution Overview
Problem
In Global Server Load Balancing (GSLB) systems, maintaining site persistence across multiple load balancers is challenging due to missing configuration information, which disrupts the ability of load balancers to honor cookies from GSLB virtual servers, leading to interrupted site persistence.
Innovation Solution
Configuring GSLB appliances and load balancers with GSLB virtual server information, including persistence identifiers, IP addresses, and service ports, to ensure site persistence by attaching GSLB cookies to HTTP responses and checking their status for appropriate redirection or proxying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If load balancers operate independently without GSLB configuration, then device complexity is reduced, but site persistence is interrupted
Solution Approach 1:
The system segments configuration management by introducing GSLB virtual servers that hold persistence configuration information, separating the complexity of site persistence management from individual load balancers. Load balancers only need to retrieve and apply configuration from GSLB virtual servers rather than maintaining complex local configurations.
Solution Approach 2:
GSLB virtual servers act as intermediaries between the client and load balancers, providing configuration information including persistence identifiers. The load balancer queries the GSLB virtual server to obtain configuration details needed to honor cookies and maintain site persistence without having complex local configuration.
2Loss of information
If load balancers have complete GSLB configuration, then site persistence is maintained, but information loss is reduced
Solution Approach 1:
The GSLB virtual server pre-configures persistence information including persistence identifiers, IP addresses, and service ports before load balancer queries. This preliminary configuration allows the load balancer to immediately honor cookies without needing to store or process complex GSLB configuration locally.
Solution Approach 2:
The load balancer queries the GSLB virtual server for configuration information based on received cookies, creating a feedback loop where configuration is retrieved on-demand. This ensures the load balancer has the necessary information to maintain site persistence without permanently storing complex GSLB configuration.
3Reliability
If cookies are honored across GSLB hierarchy, then site persistence is improved, but device complexity increases
Solution Approach 1:
The GSLB virtual server automatically provides the persistence identifier and configuration information when the load balancer queries it based on a received cookie. The system self-services the configuration retrieval process, eliminating the need for manual cookie handling configuration on the load balancer while maintaining site persistence.
Data Source
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AI summary
The present invention provides systems and methods for maintaining site persistence in a hierarchical Global Server Load Balancing (GSLB) deployment. Via configuration of GSLB services locally and remotely on each of the GSLB appliances and LB appliances at a site, a site appliance identifies and associates requests from the GSLB with the site. Furthermore, the site appliance may receive a GSLB cookie with the client request and confirms the request is from the expected GSLB in the site hierarchy. When the load balancers receives a response from a server, the appliance may include the GSLB cookie with the response back to the client. The appliance may also include an LB cookie to identify the server selected by the LB. When the client sends another request, the request may include the GSLB and LB cookie. With this information, the GSLB and LB appliance may maintain site persistence for the client as well as server persistence at the site.