moby--moby/docs/reference/commandline/swarm_init.md

swarm init

Usage:  docker swarm init [OPTIONS]

Initialize a Swarm

Options:
      --auto-accept value               Auto acceptance policy (default worker)
      --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)
      --secret string                   Set secret value needed to accept nodes into cluster
      --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.

$ docker swarm init --listen-addr 192.168.99.121:2377
No --secret provided. Generated random secret:
    4ao565v9jsuogtq5t8s379ulb

Swarm initialized: current node (1ujecd0j9n3ro9i6628smdmth) is now a manager.

To add a worker to this swarm, run the following command:
    docker swarm join --secret 4ao565v9jsuogtq5t8s379ulb \
    --ca-hash sha256:07ce22bd1a7619f2adc0d63bd110479a170e7c4e69df05b67a1aa2705c88ef09 \
    192.168.99.121:2377
$ docker node ls
ID                           HOSTNAME  MEMBERSHIP  STATUS  AVAILABILITY  MANAGER STATUS          LEADER
1ujecd0j9n3ro9i6628smdmth *  manager1  Accepted    Ready   Active        Reachable               Yes

If a secret for joining new nodes is not provided with --secret, docker swarm init will generate a random one and print it to the terminal (as seen in the example above). To initialize a swarm with no secret, use --secret "".

--auto-accept value

This flag controls node acceptance into the cluster. By default, worker nodes are automatically accepted by the cluster. This can be changed by specifying what kinds of nodes can be auto-accepted into the cluster. If auto-accept is not turned on, then node accept can be used to explicitly accept a node into the cluster.

For example, the following initializes a cluster with auto-acceptance of workers, but not managers

$ docker swarm init --listen-addr 192.168.99.121:2377 --auto-accept worker

It is possible to pass a comma-separated list of node types. The following initializes a cluster with auto-acceptance of both worker and manager nodes

$ docker swarm init --listen-addr 192.168.99.121:2377 --auto-accept worker,manager

To disable auto acceptance, use the none option. Note that this option cannot be combined with other values. When disabling auto acceptance, nodes must be manually accepted or rejected using docker node accept or docker node rm.

The following example enables swarm mode with auto acceptance disabled:

$ docker swarm init --listen-addr 192.168.99.121:2377 --auto-accept none

--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

--secret string

Secret value needed to accept nodes into the Swarm

--task-history-limit

This flag sets up task history retention limit.

Related information

• swarm join
• swarm leave
• swarm update
• node accept
• node rm