Multi-Arch Build Support

[madudding]

Enhancement Request

Multi-arch build system equivalent to docker desktop (example docker buildx)

[Use Case Example](https://www.docker.com/blog/multi-arch-images/ #)

[jandubois]

Thank you for filing this issue. This is currently not possible because nerdctl does not yet support the --platform option: containerd/nerdctl#103

For Rancher Desktop we plan to support using moby inside the VM instead of just containerd, so we can support the docker-cli on the host. This will bring multi-platform build support. Currently our image only includes the binaries for building aarch64/arm64 binaries. Would you want to target any other platforms?

This does not by itself allow running a multi-platform k8s cluster; that would require separate nodes for each platform. I've mentioned that in #588 before.

[AkihiroSuda]

Thank you for filing this issue. This is currently not possible because nerdctl does not yet support the --platform option: containerd/nerdctl#103

I guess I can almost complete this in nerdctl v0.13
containerd/nerdctl#448

[buu700]

I'm very interested in this as well, as it's currently a blocker for switching away from Docker Desktop. At a minimum, a partial implementation of the buildx API with no multi-arch support would be enough for us to get started using Rancher.

Edit: It looks like nerdctl does support what we need, and it's compatible enough with docker that we won't need to rewrite too much code. Thanks @AkihiroSuda!

[jandubois]

I believe this is all implemented already.