This minimal TCP server is written to test routing and services in any environment, but originally to understand how Kubernetes services work. Being a FROM SCRATCH container makes it a nice size for experimenting with large ReplicasSets and such. I prefer TCP directly rather than any HTTP server (as is popular) because I need insight into things that are not related to Ingress routing at all, specifically to explore cluster-to-cluster communications without HTTP (or even gRPC, which uses HTTP).

To start the service modify the docker-compose.yaml values as desired and execute the following:

docker-compose up

Or, with just docker:

docker run -it -e NAME=whatever -e PORT=3444 -p 3444:3444 rwxrob/gotcptest

Then connect to it with netcat/nc (or whatever):

nc localhost 3444