linux/system/repo/docker_legacy.yml

parameters:
  linux:
    system:
      repo:
        docker:
          source: "deb https://apt.dockerproject.org/repo ubuntu-${_param:linux_system_codename} main"
          architectures: amd64
          key_id: 58118E89F3A912897C070ADBF76221572C52609D
          key_server: keyserver.ubuntu.com