Home/ Install Docker/ Initialize SWARM
Phase 2 — Install Docker · Step 5 of 14

Initialize SWARM — Master & Slaves

Create the Docker Swarm on the MASTER node, then join all three SLAVE nodes as workers to form a single logical cluster.

Step 1 — Init the Swarm on MASTER

On the MASTER Pi, run:

Run on MASTER
$ docker swarm init --advertise-addr 192.168.0.23

Replace 192.168.0.23 with the actual IP of your MASTER Pi (from the previous step). The output will look like this:

Expected output
Swarm initialized: current node (jg3z8p6rei7yk1d18disx0j5h) is now a manager.

To add a worker to this swarm, run the following command:

    docker swarm join --token SWMTKN-1-1gp7povi99cvtn4vdcor1ehoi9l2fnkbbgasxl8sibp5osyrhx-3l6yptd5h58vssjbr52xvl9pt 192.168.0.23:2377

To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
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Copy the join command — you'll need to paste it on each SLAVE node in the next step. The token is unique to your swarm.

Step 2 — Join SLAVE Nodes

On each SLAVE (SLAVE1, SLAVE2, SLAVE3), paste and run the join command from the output above:

Run on SLAVE1, SLAVE2 and SLAVE3
$ docker swarm join \
  --token SWMTKN-1-1gp7povi99cvtn4vdcor1ehoi9l2fnkbbgasxl8sibp5osyrhx-3l6yptd5h58vssjbr52xvl9pt \
  192.168.0.23:2377

# Expected output:
This node joined a swarm as a worker.

Step 3 — Verify the Cluster

Back on the MASTER, verify all 4 nodes are in the swarm:

Run on MASTER
$ docker node ls

ID                HOSTNAME  STATUS  AVAILABILITY  MANAGER STATUS
jg3z8p6rei7yk *  MASTER    Ready   Active        Leader
abc456def789     SLAVE1    Ready   Active
ghi012jkl345     SLAVE2    Ready   Active
mno678pqr901     SLAVE3    Ready   Active

Check Swarm Status with docker info

Verify swarm is active
$ docker info | grep -A 5 Swarm
 Swarm: active
  NodeID: jg3z8p6rei7yk1d18disx0j5h
  Is Manager: true
  ClusterID: 1pf6vk1h3zx0b2dxbf2i0cg1v
  Managers: 1
  Nodes: 4
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Official documentation: docs.docker.com — docker swarm init