[v2] Revamp Container Builds

[c-kruse]

In skupper today we build and publish x86_64 and arm64 images. The way we build and publish these is not ideal, and we could use the 2.0 version as an opportunity to improve.

Suggested outcome(s)

• The images we test with (pending integration/e2e tests) should be the same images we publish. Today we completely rebuild images to push after CI passes.

• All images contain stripped down statically linked skupper executable(s) that are appropriate for the base image.

  • Presently we produce a mix of results in this department: amd64 images have a dynamically linked skupper binaries baked into ubi9 images that were produced from a debian 12 based builder (asking for trouble), arm64 images have a static pure-go binary. We've taken similar steps for our skupper cli binary that we distribute.
  • All of the executables end up fairly large with debugging and dwarf symbols that could be stripped to shave ~20MB uncompressed. If somebody has ever installed gdb in container and attached to a running skupper process I'd be shocked.

Open Questions

We have been intentionally publishing docker formatted images over OCI images - maybe in order to support OCP 3? Can we move to oci images? does it matter?

Should we publish image tags with platform suffixes in addition to our main index/list images? i.e. quay.io/skupper/controller:2.0.0-linux-arm64

Should we publish test images on PR? (i.e. quay.io/skupper/dev/controller:ci-$(git rev-parse HEAD)) to make it easier for peers to review without checking out the branch and self-building images?

[c-kruse]

Resolved by https://github.com/skupperproject/skupper/pull/1767

Resolutions:

• We are moving forward with publishing OCI artifacts for now
• Skupper binaries in the images are now more consistent
• CI images are ready and set up for out-of-process tests (that is tests ran on podman/docker/kind/minikube)
• For now, no changes to publishing arch-specific image tags or image publish frequency, although releases now include a digests.yaml that could help (has per-platform image digests)