Makefile, contrib: Add script to create kind cluster

[christarazi]

We have the equivalent for minikube.

Usage:

$ ./contrib/scripts/kind.sh
$ # or
$ make kind

[rolinh]

* Find a way to parameterize the number of workers (not sure how
  necessary this is)

I use kind a lot for Hubble Relay development and, in this context, being able to test with 4+ nodes is super useful (I've created kind clusters up to 50 nodes).

However, I also found out that I don't need a local registry as I can just kind load docker-image cilium/hubble-relay:latest (and any other relevant image) followed by kubectl delete pods .... This works because the pull policy is IfNotPresent and if there are multiple images with the same tag, the most recent one is picked.

[sayboras]

I love kind a lot as well. Have been using it as part of local development and testing.

Related on number of node, here is the configuration we used in smoke test with one tweak to make sure that the control plan is available for scheduling. https://github.com/cilium/cilium/blob/master/.github/kind-config.yaml#L6

[joestringer]

FWIW, I feel it'd be kinda nice to have some convenience script for this in the tree, occasionally I use the steps from the conformance tests + .github/kind-config.yaml to deploy a kind config but I always have to look it up again whenever I try it out.

[christarazi]

Yeah, I think it's worth dusting off this PR and getting it out even though it doesn't meet all the TODOs marked in the PR description. I often switch to this branch locally, create my kind cluster, then switch back to my dev branch 😅.

/cc @sayboras, he had a similar PR out and might be worth figuring out which one to move forward and whether to consolidate.

[sayboras]

@joestringer @christarazi 👋 oh the pending PR I got is my local script to quickly run conformance test. There are few comments which I need to address, but didn't have time recently. I will plan sometimes to clean it up, anyway, happy to discuss how to move forward in either case 😃

[aditighag]

👍 Are you planning to add more steps to install cilium to the same script?