Add github-action and Dockerfile for multi-arch build

[toelke]

The need for this change has been discussed in piraeusdatastore/piraeus#74

This change is probably not extremely elegant; I saw that the operator-sdk-version used by this repository is quite old. I am circumventing it here by "manually" building the go-code during building the docker image.

I do not expect this to be merged like this, but I want to start a discussion...

[WanzenBug]

On the whole, I'm not against removing operator-sdk from the build process. I think that's what happens in newer operator-sdk versions anyways. We are only using such an old versions because nobody has the time to upgrade.

operator-sdk doesn't actually do anything during the build, just calls go build. Ideally, we would just run go build with GOARCH=amd64 and once with GOARCH=arm64, and copy the artifact into gcr.io/distroless/static. I don't think we need anything from debian.

[toelke]

I am doing the first part of this using docker build containers -- that seemed easier for me :-|

I will look into putting the result into distroless and see what happens.

[toelke]

So running distroless (but not static) is working for both arm64 and amd64.

[WanzenBug]

Overall looks good. I'd still like to try creating a distroless/static image and also removing:

• the existing dockerfile + helper scripts
• the existing github action that builds+pushes using operator-sdk

[WanzenBug]

Don't delete the whole makefile. Just replace this line with docker build -t $(PROJECT):$(TAG) --no-cache=$(NOCACHE) -f build/Dockerfile.multiarch .

[WanzenBug]

Needs to changed to -f build/Dockerfile now

[toelke]

About the failing pre-commit hook that checks for a correkt operator-sdk-setup: Should I remove the hook or should I rename the Dockerfile?

[WanzenBug]

About the failing pre-commit hook that checks for a correkt operator-sdk-setup: Should I remove the hook or should I rename the Dockerfile?

Please rename the dockerfile, we still need a working operator-sdk for some things.

[toelke]

Thank you so much for your patience and all the good tips!

[WanzenBug]

Almost ready to merge, just missing the one fix on the Makefile. Already gave it a test run, seems to be working without issue, and we have a smaller image too 👍

[WanzenBug]

🎉

[toelke]

Thanks again