Digital Ocean cloud-config script for Ubuntu 16

cloud-init-dokku-post.yaml

#cloud-config
# Configures a basic Ubuntu box.
# * Installs a few common packages
# * Disables root login
# * Disables password login
# * Creates a user in the sudo, www-data groups
#
# Follow the log by ssh-ing in and running: `tail -f /var/log/cloud-init-output.log`
apt_update: true
apt_upgrade: true
packages:
  - language-pack-en
  - build-essential
  - curl
  - g++
  - gcc
  - git
  - libssl-dev
  - make
  - openssl
users:
  - name: app
    groups: sudo
    shell: /bin/bash
    sudo: ['ALL=(ALL) NOPASSWD:ALL']
    lock-passwd: true # no password login
    ssh-authorized-keys:
      - PUB_KEY
runcmd:
  # Disable root ssh login and add our own new user: app
  # Also add dokku user to support commands over SSH
  - echo "Editing sshd_config"
  - sed -i -e '/^PermitRootLogin/s/^.*$/PermitRootLogin no/' /etc/ssh/sshd_config
  - sed -i -e '$aAllowUsers app dokku' /etc/ssh/sshd_config
  - service ssh restart

DO says that cloud-config is only available on CoreOS, Ubuntu 14, and CentOS 7.