cloud-config file for enabling swap on CoreOS

cloud-config

#cloud-config

coreos:
  units:
    - name: systemd-sysctl.service
      command: restart
    - name: create-swap.service
      command: start
      runtime: true
      content: |
        [Unit]
        Description=Create swap file
        Before=swap.service

        [Service]
        Type=oneshot
        Environment="SWAPFILE=/2GiB.swap"
        ExecStart=/usr/bin/touch ${SWAPFILE}
        ExecStart=/usr/bin/chattr +C ${SWAPFILE}
        ExecStart=/usr/bin/fallocate -l 2048m ${SWAPFILE}
        ExecStart=/usr/bin/chmod 600 ${SWAPFILE}
        ExecStart=/usr/sbin/mkswap ${SWAPFILE}

        [Install]
        WantedBy=multi-user.target
    - name: swap.service
      command: start
      content: |
        [Unit]
        Description=Turn on swap

        [Service]
        Type=oneshot
        Environment="SWAPFILE=/2GiB.swap"
        RemainAfterExit=true
        ExecStartPre=/usr/sbin/losetup -f ${SWAPFILE}
        ExecStart=/usr/bin/sh -c "/sbin/swapon $(/usr/sbin/losetup -j ${SWAPFILE} | /usr/bin/cut -d : -f 1)"
        ExecStop=/usr/bin/sh -c "/sbin/swapoff $(/usr/sbin/losetup -j ${SWAPFILE} | /usr/bin/cut -d : -f 1)"
        ExecStopPost=/usr/bin/sh -c "/usr/sbin/losetup -d $(/usr/sbin/losetup -j ${SWAPFILE} | /usr/bin/cut -d : -f 1)"

        [Install]
        WantedBy=multi-user.target
write_files:
  - path: /etc/sysctl.d/swap.conf
    permissions: 0644
    owner: root
    content: |
      vm.swappiness=10
      vm.vfs_cache_pressure=50