root@master:~# docker swarm --help
Usage: docker swarm COMMAND
Manage Swarm
Options:
--help Print usage
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
Run 'docker swarm COMMAND --help' for more information on a command.