<!--[metadata]>
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title = "swarm init"
description = "The swarm init command description and usage"
keywords = ["swarm, init"]
advisory = "rc"
[menu.main]
parent = "smn_cli"
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<![end-metadata]-->

# swarm init

```markdown
Usage:  docker swarm init [OPTIONS]

Initialize a swarm

Options:
      --cert-expiry duration            Validity period for node certificates (default 2160h0m0s)
      --dispatcher-heartbeat duration   Dispatcher heartbeat period (default 5s)
      --external-ca value               Specifications of one or more certificate signing endpoints
      --force-new-cluster               Force create a new cluster from current state.
      --help                            Print usage
      --listen-addr value               Listen address (default 0.0.0.0:2377)
      --task-history-limit int          Task history retention limit (default 10)
```

Initialize a swarm cluster. The docker engine targeted by this command becomes a manager
in the newly created one node swarm cluster.


```bash
$ docker swarm init --listen-addr 192.168.99.121:2377
Swarm initialized: current node (bvz81updecsj6wjz393c09vti) is now a manager.

To add a worker to this swarm, run the following command:
    docker swarm join \
    --token SWMTKN-1-3pu6hszjas19xyp7ghgosyx9k8atbfcr8p2is99znpy26u2lkl-1awxwuwd3z9j1z3puu7rcgdbx \
    172.17.0.2:2377

To add a manager to this swarm, run the following command:
    docker swarm join \
    --token SWMTKN-1-3pu6hszjas19xyp7ghgosyx9k8atbfcr8p2is99znpy26u2lkl-7p73s1dx5in4tatdymyhg9hu2 \
    172.17.0.2:2377
```

`docker swarm init` generates two random tokens, a worker token and a manager token. When you join
a new node to the swarm, the node joins as a worker or manager node based upon the token you pass
to [swarm join](swarm_join.md).

After you create the swarm, you can display or rotate the token using
[swarm join-token](swarm_join_token.md).

### `--cert-expiry`

This flag sets the validity period for node certificates.

### `--dispatcher-heartbeat`

This flags sets the frequency with which nodes are told to use as a
period to report their health.

### `--external-ca value`

This flag sets up the swarm to use an external CA to issue node certificates. The value takes
the form `protocol=X,url=Y`. The value for `protocol` specifies what protocol should be used
to send signing requests to the external CA. Currently, the only supported value is `cfssl`.
The URL specifies the endpoint where signing requests should be submitted.

### `--force-new-cluster`

This flag forces an existing node that was part of a quorum that was lost to restart as a single node Manager without losing its data

### `--listen-addr value`

The node listens for inbound swarm manager traffic on this IP:PORT

### `--task-history-limit`

This flag sets up task history retention limit.

## Related information

* [swarm join](swarm_join.md)
* [swarm leave](swarm_leave.md)
* [swarm update](swarm_update.md)
* [swarm join-token](swarm_join_token.md)
* [node rm](node_rm.md)