title: How to automate Multi-Arch-Docker Image builds
body: <p>I have dockerized a nodejs app on github. My Dockerfile is based on the offical nodejs images. The offical node-repo supports multiple architectures (x86, amd64, arm) seamlessly. This means I can build the exact same Dockerfile on different machines resulting in different images for the respective architecture.</p>
  
  <p>So I am trying to offer the same architectures seamlessly for my app, too. But how?
  My goal is automate it as much as possible.
  I know I need in theory to create a docker-manifest, which acts as a docker-repo and redirects the end-users-docker-clients to their suitable images.</p>
  
  <p>Docker-Hub itself can monitor a github repo and kick off an automated build. Thats would take care of the amd64 image. But what about the remaining architectures?
  There is also the service called 'TravisCI' which I guess could take care of the arm-build with the help of qemu.
  Then I think both repos could then be referenced statically by the manifest-repo. But this still leaves a couple architectures unfulfilled.</p>
  
  <p>But using multiple services/ways of building the same app feels wrong. Does anyone know a better and more complete solution to this problem?
  It's basically running the same dockerfile through a couple machines and recording them in a manifest.</p>