When you first create a swarm, you place a single Docker Engine into swarm mode. To take full advantage of swarm mode you can add nodes to the swarm:
Before you add nodes to a swarm you must install Docker Engine 1.12 or later on the host machine.
The Docker Engine joins the swarm depending on the join-token you provide to the
docker swarm join command. The node only uses the token at join time. If you subsequently rotate the token, it doesn’t affect existing swarm nodes. Refer to Run Docker Engine in swarm mode.
Note: Docker engine allows a non-FIPS node to join a FIPS-enabled swarm cluster.
While a mixed FIPS environment makes upgrading or changing status easier, Docker recommends not running a mixed FIPS environment in production.
To retrieve the join command including the join token for worker nodes, run the following command on a manager node:
$ docker swarm join-token worker To add a worker to this swarm, run the following command: docker swarm join \ --token SWMTKN-1-49nj1cmql0jkz5s954yi3oex3nedyz0fb0xx14ie39trti4wxv-8vxv8rssmk743ojnwacrr2e7c \ 192.168.99.100:2377
Run the command from the output on the worker to join the swarm:
$ docker swarm join \ --token SWMTKN-1-49nj1cmql0jkz5s954yi3oex3nedyz0fb0xx14ie39trti4wxv-8vxv8rssmk743ojnwacrr2e7c \ 192.168.99.100:2377 This node joined a swarm as a worker.
docker swarm join command does the following:
Activeavailability, meaning it can receive tasks from the scheduler.
ingressoverlay network to the current node.
When you run
docker swarm join and pass the manager token, the Docker Engine switches into swarm mode the same as for workers. Manager nodes also participate in the raft consensus. The new nodes should be
Reachable, but the existing manager remains the swarm
Docker recommends three or five manager nodes per cluster to implement high availability. Because swarm mode manager nodes share data using Raft, there must be an odd number of managers. The swarm can continue to function after as long as a quorum of more than half of the manager nodes are available.
For more detail about swarm managers and administering a swarm, see Administer and maintain a swarm of Docker Engines.
To retrieve the join command including the join token for manager nodes, run the following command on a manager node:
$ docker swarm join-token manager To add a manager to this swarm, run the following command: docker swarm join \ --token SWMTKN-1-61ztec5kyafptydic6jfc1i33t37flcl4nuipzcusor96k7kby-5vy9t8u35tuqm7vh67lrz9xp6 \ 192.168.99.100:2377
Run the command from the output on the new manager node to join it to the swarm:
$ docker swarm join \ --token SWMTKN-1-61ztec5kyafptydic6jfc1i33t37flcl4nuipzcusor96k7kby-5vy9t8u35tuqm7vh67lrz9xp6 \ 192.168.99.100:2377 This node joined a swarm as a manager.
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