Building Docker Containers for ARM with buildx

I’ve spent some time over the holidays building a Kubernetes cluster running on raspberry pis. One issue I ran into was that not all docker images I wanted to run were available for arm/linux. Luckily there’s a useful tool called buildx that extends Docker to build containers for different platforms and architectures using quemu and binfmt. ARM has a blog post that details the steps needed to build images.

The steps are:

There appears to be a bug where the builder loses the other supported platforms after a reboot/restart but removing the builder and readding it seems to fix it.