docker containers will not work on an ARM machine

I try to make gitlab CI builds work using docker on an ARM machine. It works fine on x86_64, but not on ARM. The issue seems to be with the gitlab/gitlab-runner:* images. They are based on an x86_64 image, which thus gives me an System error: exec format error error when running them.

My own image works fine on ARM, I can run it. Only issue is with the build and cache gitlab runner docker images. This means that although you currently do host arm gitlab ci .deb packages, these are apparently not yet compatible with the docker approach. Would be nice if such runners could be added :)

I will look into patching the dockerfiles such that I get ARM based gitlab/gitlab-runner:build and gitlab/gitlab-runner:cache images.