Docker only with a valume

docker-only-with-volume.yml

#cloud-config

coreos:
  units:
    - name: format-ephemeral.service
      command: start
      content: |
        [Unit]
        Description=Formats the ephemeral drive
        [Service]
        Type=oneshot
        RemainAfterExit=yes
        ExecStart=/bin/sh -c '/usr/sbin/blkid -pi /dev/vda | grep TYPE= || /usr/sbin/mkfs.ext4 /dev/vda'

    - name: var-lib-docker.mount
      command: start
      content: |
        [Unit]
        Description=Mount ephemeral to /var/lib/docker
        Requires=format-ephemeral.service
        After=format-ephemeral.service
        Before=docker.service

        [Mount]
        What=/dev/vda
        Where=/var/lib/docker
        Type=ext4

    - name: docker-tcp.socket
      command: start
      enable: true
      content: |
        [Unit]
        Description=Docker Socket for the API

        [Socket]
        ListenStream=2375
        BindIPv6Only=both
        Service=docker.service

        [Install]
        WantedBy=sockets.target