Droplet anchor IP configuration for CoreOS cloud-config on Digital Ocean

gistfile1.txt

#cloud-config

coreos:
  units:
    # Explicit anchor IP configuration required on CoreOS stable droplet.
    # <https://www.digitalocean.com/community/tutorials/how-to-enable-floating-ips-on-an-older-droplet>
    - name: droplet-anchor-ip.service
      command: start
      content: |
        [Unit]
        Description=Droplet anchor IP

        [Service]
        Type=oneshot
        RemainAfterExit=true
        ExecStart=/usr/bin/sh -c "anchor_ipv4=$(curl --silent http://169.254.169.254/metadata/v1/interfaces/public/0/anchor_ipv4/address); ip addr | grep --silent $${anchor_ipv4} || ip addr add $${anchor_ipv4}/16 dev eth0"

        [Install]
        WantedBy=multi-user.target