Swarm mode

  • Since version 1.12, the Docker Engine embeds SwarmKit

  • All the SwarmKit features are "asleep" until you enable "Swarm mode"

  • Examples of Swarm Mode commands:

    • docker swarm (enable Swarm mode; join a Swarm; adjust cluster parameters)

    • docker node (view nodes; promote/demote managers; manage nodes)

    • docker service (create and manage services)


  • The Docker API exposes the same concepts

  • The SwarmKit API is also exposed (on a separate socket)

Swarm mode needs to be explicitly activated

  • By default, all this new code is inactive

  • Swarm mode can be enabled, "unlocking" SwarmKit functions
    (services, out-of-the-box overlay networks, etc.)

  • Try a Swarm-specific command:
    docker node ls

You will get an error message:

Error response from daemon: This node is not a swarm manager. [...]