Transparent Load Balancer Clusters That Preserve Client IPs
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Solution Overview
Problem
Existing load balancer clusters cannot scale out when applications require client IP addresses for processing, as designating one active load balancer as a default gateway prevents additional load balancers from being added.
Innovation Solution
Implement a cluster of transparent load balancers that concurrently receive and forward client traffic without modifying source IP addresses, with active load balancers providing flow information to a default gateway for responsive message forwarding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If one active load balancer is designated as default gateway, then response traffic can be properly forwarded, but load balancer cluster cannot scale out
Solution Approach 1:
The patent segments the load balancer cluster into multiple active load balancers that can independently handle traffic, with each maintaining its own default gateway relationship. This allows the system to scale out by adding more active load balancers without compromising response traffic forwarding capability, as each load balancer in the cluster can independently manage its own gateway functions.
Solution Approach 2:
The patent implements multi-functionality by enabling each active load balancer to serve dual purposes: both as a traffic distribution point and as a potential default gateway. This universal design allows any load balancer in the cluster to assume gateway responsibilities, eliminating the limitation where only one load balancer could be the default gateway while others remained inactive.
2Adaptability or versatility
If load balancer modifies source IP address, then load balancer cluster is scalable, but server cannot receive client IP address for processing
Solution Approach 1:
The patent applies local quality by enabling selective IP address translation at different stages of traffic flow. The load balancer performs SNAT (source network address translation) when forwarding traffic to backend servers to maintain scalability, but simultaneously preserves the original client IP address information through additional mechanisms such as tunneling or header manipulation, allowing servers to access client IP data when needed without compromising the load balancing scalability benefit.
Data Source
AI summary
Some embodiments provide a method of performing load balancing on client traffic sent to a cluster of servers that are associated with a common network address (e.g., for a VIP address associated with a service provided by the cluster of servers). The method assigns a cluster of two or more transparent load balancers to the common network address associated with the server cluster. The method configures at least two of these transparent load balancers as active transparent load balancers that concurrently (1) receive data message flows sent by clients directed to the common network address, (2) select one of the servers for each flow, and (3) forward each flow to the server selected for the flow without modifying a source network address (e.g., IP network address) of the flow.