CoreOS + Etcd + Flannel = Pretty Cool (user-data)

user-data

#cloud-config

---
coreos:
  etcd:
    addr: $public_ipv4:4001
    peer-addr: $public_ipv4:7001
    discovery: https://discovery.etcd.io/ff10c58e472358739a4d57e315cc94f3
  fleet:
    public-ip: $public_ipv4
  flannel:
    interface: $public_ipv4
  units:
  - name: etcd.service
    command: start
  - name: fleet.service
    command: start
  - name: docker-tcp.socket
    command: start
    enable: true
    content: |
      [Unit]
      Description=Docker Socket for the API

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

      [Install]
      WantedBy=sockets.target
  - name: flanneld.service
    drop-ins:
    - name: 50-network-config.conf
      content: |
        [Service]
        ExecStartPre=/usr/bin/etcdctl set /coreos.com/network/config '{ "Network": "10.1.0.0/16" }'
    command: start