I've been following the steps in this article to set up a Docker swarm cluster on a pair of Raspberry Pis. Most of the steps work as-is from Mac OS, but for a few steps, there are a couple of variations.
cat ~/.ssh/id_rsa.pub | ssh user@machine "mkdir ~/.ssh; cat >> ~/.ssh/authorized_keys"
eval $(docker-machine env pi1)
where pi1 is the name of the remote host.
eval "$(docker-machine env -u)"
More to come in part 2.