Create a swarm

After you complete the tutorial setup steps, you’re ready to create a swarm. Make sure the Docker Engine daemon is started on the host machines.

1. Open a terminal and ssh into the machine where you want to run your manager node. This tutorial uses a machine named manager1. If you use Docker Machine, you can connect to it via SSH using the following command:

   $ docker-machine ssh manager1
   

2. Run the following command to create a new swarm:

   docker swarm init --advertise-addr <MANAGER-IP>
   

   Note: If you are using Docker for Mac or Docker for Windows to test single-node swarm, simply run docker swarm init with no arguments. There is no need to specify --advertise-addr in this case. To learn more, see the topic on how to Use Docker for Mac or Docker for Windows with Swarm.

   In the tutorial, the following command creates a swarm on the manager1 machine:

   $ docker swarm init --advertise-addr 192.168.99.100
   Swarm initialized: current node (dxn1zf6l61qsb1josjja83ngz) is now a manager.
   
   To add a worker to this swarm, run the following command:
   
       docker swarm join \
       --token SWMTKN-1-49nj1cmql0jkz5s954yi3oex3nedyz0fb0xx14ie39trti4wxv-8vxv8rssmk743ojnwacrr2e7c \
       192.168.99.100:2377
   
   To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
   

   The --advertise-addr flag configures the manager node to publish its address as 192.168.99.100. The other nodes in the swarm must be able to access the manager at the IP address.

   The output includes the commands to join new nodes to the swarm. Nodes will join as managers or workers depending on the value for the --token flag.

3. Run docker info to view the current state of the swarm:

   $ docker info
   
   Containers: 2
   Running: 0
   Paused: 0
   Stopped: 2
     ...snip...
   Swarm: active
     NodeID: dxn1zf6l61qsb1josjja83ngz
     Is Manager: true
     Managers: 1
     Nodes: 1
     ...snip...
   

4. Run the docker node ls command to view information about nodes:

   $ docker node ls
   
   ID                           HOSTNAME  STATUS  AVAILABILITY  MANAGER STATUS
   dxn1zf6l61qsb1josjja83ngz *  manager1  Ready   Active        Leader
   
   

   The * next to the node ID indicates that you’re currently connected on this node.

   Docker Engine swarm mode automatically names the node for the machine host name. The tutorial covers other columns in later steps.

What’s next?

In the next section of the tutorial, we’ll add two more nodes to the cluster.