plan examples::swarm(TargetSpec $managers, TargetSpec $workers) {
  $hosts = [$managers, $workers]
  $hosts.apply_prep
  apply($hosts) {
    include 'docker'
  }

  # Initialize the swarm on a single manager.
  $targets = get_targets($managers)
  $master = $targets[0]
  $init_result = run_command('docker swarm init', $master, _catch_errors => true)
  # Allow init to fail in case we're running it again. Log the result.
  notice($init_result)

  $manager_token = run_command('docker swarm join-token manager --quiet', $master).first['stdout'].chomp
  $mgr_result = run_command("docker swarm join --token ${manager_token} ${$master.host}:2377", $targets[1,-1], _catch_errors => true)
  notice($mgr_result)

  $worker_token = run_command('docker swarm join-token worker --quiet', $master).first['stdout'].chomp
  return run_command("docker swarm join --token ${worker_token} ${$master.host}:2377", $workers)
}