Since all the functionality to set up a Docker Swarm cluster is already included in the Docker installation, this is actually a really easy thing to do. Let's see what commands we have available to us:

$ docker swarm
<snip>
Commands:
  init        Initialize a swarm
  join        Join a swarm as a node and/or manager
  join-token  Manage join tokens
  leave       Leave the swarm
  unlock      Unlock swarm
  unlock-key  Manage the unlock key
  update      Update the swarm

A few things to note here--some more apparent than others:

• You create a swarm with docker swarm init
• You join a cluster with docker swarm join and the machine can be a worker node, a manager node, or both
• Authentication is managed using tokens (unique strings that need to match)
• If something happens to a manager node, such as a restart or power cycle, and you have set up auto-locking of the swarm, you will need an unlock key to unlock the TLS keys

So far, so good, so let's see whether we can set up a swarm with our machine serving both as a manager and a worker to see how this works.