gRPC client side load balancing

Question

I\'m using gRPC with Python as client/server inside kubernetes pods... I would like to be able to launch multiple pods of the same type (gRPC servers) and let the client connect

Answer 1

Usual K8S load balancing doesn't work for gRPC. The following link explains why. https://kubernetes.io/blog/2018/11/07/grpc-load-balancing-on-kubernetes-without-tears/

This is because gRPC is built on HTTP/2, and HTTP/2 is designed to have a single long-lived TCP connection, across which all requests are multiplexed—meaning multiple requests can be active on the same connection at any point in time. Normally, this is great, as it reduces the overhead of connection management. However, it also means that (as you might imagine) connection-level balancing isn’t very useful. Once the connection is established, there’s no more balancing to be done. All requests will get pinned to a single destination pod.

Most modern ingress controllers can handle this, but they are either hot of the oven (nginx), or in alpha version (traefik), or require the latest version of K8S (Linkerd). You can do client-side load balancing, of which you can find a Java solution here.