moby/docs/swarm/swarm-tutorial/add-nodes.md

Add nodes to the swarm

Once you've created a swarm with a manager node, you're ready to add worker nodes.

1. Open a terminal and ssh into the machine where you want to run a worker node. This tutorial uses the name worker1.

2. Run the command produced by the docker swarm init output from the Create a swarm tutorial step to create a worker node joined to the existing swarm:

   $ docker swarm join --secret 4ao565v9jsuogtq5t8s379ulb \
     --ca-hash sha256:07ce22bd1a7619f2adc0d63bd110479a170e7c4e69df05b67a1aa2705c88ef09 \
     192.168.99.100:2377
   

   If you don't have the command available, you can run the following command:

   docker swarm join --secret <SECRET> <MANAGER-IP>:<PORT>
   

   Replace <SECRET> with the secret that was printed by docker swarm init in the previous step. Replace <MANAGER-IP> with the address of the manager node and <PORT> with the port where the manager listens.

   The command generated from docker swarm init includes the --ca-hash to securely identify the manager node according to its root CA. For the tutorial, it is OK to join without it.

3. Open a terminal and ssh into the machine where you want to run a second worker node. This tutorial uses the name worker2.

4. Run the command produced by the docker swarm init output from the Create a swarm tutorial step to create a second worker node joined to the existing swarm:

   $ docker swarm join --secret 4ao565v9jsuogtq5t8s379ulb \
     --ca-hash sha256:07ce22bd1a7619f2adc0d63bd110479a170e7c4e69df05b67a1aa2705c88ef09 \
     192.168.99.100:2377
   

5. Open a terminal and ssh into the machine where the manager node runs and run the docker node ls command to see the worker nodes:

   ID                           HOSTNAME  MEMBERSHIP  STATUS  AVAILABILITY  MANAGER STATUS  LEADER
   03g1y59jwfg7cf99w4lt0f662    worker2   Accepted    Ready   Active
   9j68exjopxe7wfl6yuxml7a7j    worker1   Accepted    Ready   Active
   dxn1zf6l61qsb1josjja83ngz *  manager1  Accepted    Ready   Active        Reachable       Yes
   

   The MANAGER column identifies the manager nodes in the swarm. The empty status in this column for worker1 and worker2 identifies them as worker nodes.

   Swarm management commands like docker node ls only work on manager nodes.

What's next?

Now your swarm consists of a manager and two worker nodes. In the next step of the tutorial, you deploy a service to the swarm.