Hi @jeremie.drouet, I used your blog post as inspiration for my attempt at multiarch, but it seems that something has changed recently in the GitLab runner code that causes your example to stop working.
After busting my head against the wall for a while, I had to add the following lines to my .gitlab-ci.yml to properly register the binfmt headers:
before_script:
- docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
Without this, I kept getting the following error:
failed to solve: rpc error: code = Unknown desc = failed to load LLB: runtime execution on platform linux/arm/v7 not supported
Now my multiarch build completes successfully for armv6, armv7, and aarch64 on public runners.
Here is my full multiarch .gitlab-ci.yml for reference:
https://github.com/oofnikj/nuttssh/blob/multiarch/.gitlab-ci.yml