Learn more about Kubernetes L4 Load Balancer from our experts. Our Kubernetes team is here to help you with your questions and concerns.

Kubernetes L4 Load Balancer | An Introduction

In Kubernetes, a Layer 4 (L4) load balancer is a type of load balancer that operates at the transport layer of the OSI model. It helps distribute network traffic evenly across multiple backend services or pods within a Kubernetes cluster based on network protocol information such as IP addresses and port numbers.

Furthermore, Kubernetes itself does not provide a built-in L4 load balancer. However, Kubernetes integrates with various cloud providers or networking solutions that offer L4 load balancing capabilities. These load balancers can be external to the cluster or integrated into the underlying infrastructure.

When a request is made to a service in a Kubernetes cluster, the L4 load balancer receives the incoming network traffic. It then forwards it to one of the backend services or pods based on the load balancing algorithm configured. The load balancer performs basic health checks on the backend services to ensure they are available before routing traffic to them.

The incoming request is accepted by the load balancer, and based on a set of rules, the traffic is sent to the destination IP address and port.

Layer-4 load balancer forwards traffic to Nodeports. Additionally, it allows us to forward both HTTP and TCP traffic.

In most cases, the underlying cloud provide supports the L4 load balancer. Hence, when we deploy RKE clusters on bare-metal servers and vSphere clusters, Layer-4 load balancer is not supported.

Our experts would like to point out that Kubernetes also supports Layer 7 (L7) load balancing. It operates at the application layer of the OSI model. Additionally, L7 load balancers can make routing decisions based on more granular information, like HTTP headers, allowing for advanced traffic routing and request manipulation.

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Conclusion

To conclude, our Support Techs introduced us to Kubernetes Layer 4 Load Balancer.