Create multi-arch builds

[stevehipwell]

The current docker images are separated by architecture & OS instead of just OS which makes consuming them hard in a multi-arch environment.

It would be easy to verify if this pattern would work by making some minor changes to the current GH action, I'd be happy to open a PR to configure this. The current make pattern could then be updated to use docker buildx build which would create a multi-arch image. The final step could be to switch to GH actions for image building, I'm also happy to open a PR to do this (with some help understanding exactly how the current process works).

[patrick-stephens]

We're doing all this for Fluent Bit so makes sense to me - we're also pushing to ghcr.io there and then only promoting to DockerHub for releases. Note for PRs you have to support forks and restricted permissions due to them, i.e. not being able to push to a registry otherwise you can leak the credentials but you can build and upload/download fine in a PR.

[chancez]

Related, anyone know if there's an easy way for downstream consumers to build a multi arch image without having to build two separate images in two separate pipelines and stitch them together into a single manifest list? Or is that the only option?

[stevehipwell]

@chancez there are a couple of examples of re-building this image as multi-arch you can find. My stevehipwell/fluentd-aggregator repo does it as a stop gap until this issue is addressed.