gRPC Name Resolution and Load Balancing on Kubernetes

This project aims to picture things that were described in my blog post:

gRPC Name Resolution & Load Balancing on Kubernetes: Everything you need to know (and probably a bit more)

Intructions:

1. Install a local Kind cluster named kind and a namespace called test. Then add a context to your Kubernetes config file with this cluster and namespace and name the cluster kind-kind-test

   https://kind.sigs.k8s.io/docs/user/quick-start/

2. Use commands in the root Makefile in order to build (and probably push) the Docker images for http and gRPC services. If you wanted to push the images to a registry as well, make sure to export PUSH=1 and change the registry names in respecitve Makefiles from mine to yours (http Makefile, gRPC Makefile)

   export PUSH=1 # if you want to push them to a registry as well
   make both-http
   make both-grpc

3. Follow the instructions to setup LinkerD on your machine:

   https://linkerd.io/2.14/getting-started/

4. Apply the k8s files to your local cluster (http k8s files, gRPC k8s files) :

   kubectl apply -f -R k8s/

5. You can use tools like stern in order to observe logs from different pods simultaniously

   https://github.com/stern/stern

   # in shell number 1
   stern post-api
   # in shell number 2
   stern post-storage

6. Inject LinkerD to your deployments (http or gRPC, but gRPC is probably more interesting) and observe that the requests as being load balanced as opposed to the previous attempts in which all the requests landed on the same pod:

   make inject-grpc-linkerd
   # or 
   make inject-http-linkerd

Further changes

I'm planning to add a custom name resolver in order to create a client side load balancing solution as well. Stay tuned for that

Enjoy!