In order to enable automated builds for ARM Docker containers on Intel hosts, the Docker images must contain the qemu-arm-static binary. For that reason, the base image sedden/rpi-raspbian-qemu exists:

Enable automated builds for ARM containers on Travis CI

Automated builds can easily be enabled on Travis CI. binfmt-support is used to register ARM binaries to be executed by /usr/bin/qemu-arm-static.

The .travis.yml must contain this part:

before_script:
  - sudo apt-get --yes --no-install-recommends install binfmt-support qemu-user-static
  - echo ':arm:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/bin/qemu-arm-static:' | sudo tee -a /proc/sys/fs/binfmt_misc/register