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swarm init | The swarm init command description and usage | swarm, init |
swarm init
Usage: docker swarm init [OPTIONS]
Initialize a swarm
Options:
--advertise-addr string Advertised address (format: <ip|interface>[:port])
--autolock Enable manager autolocking (requiring an unlock key to start a stopped manager)
--availability string Availability of the node ("active"|"pause"|"drain") (default "active")
--cert-expiry duration Validity period for node certificates (ns|us|ms|s|m|h) (default 2160h0m0s)
--dispatcher-heartbeat duration Dispatcher heartbeat period (ns|us|ms|s|m|h) (default 5s)
--external-ca external-ca Specifications of one or more certificate signing endpoints
--force-new-cluster Force create a new cluster from current state
--help Print usage
--listen-addr node-addr Listen address (format: <ip|interface>[:port]) (default 0.0.0.0:2377)
--max-snapshots uint Number of additional Raft snapshots to retain
--snapshot-interval uint Number of log entries between Raft snapshots (default 10000)
--task-history-limit int Task history retention limit (default 5)
Description
Initialize a swarm. The docker engine targeted by this command becomes a manager in the newly created single-node swarm.
Examples
$ docker swarm init --advertise-addr 192.168.99.121
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 'docker swarm join-token manager' and follow the instructions.
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.
After you create the swarm, you can display or rotate the token using swarm join-token.
--autolock
This flag enables automatic locking of managers with an encryption key. The
private keys and data stored by all managers will be protected by the
encryption key printed in the output, and will not be accessible without it.
Thus, it is very important to store this key in order to activate a manager
after it restarts. The key can be passed to docker swarm unlock
to reactivate
the manager. Autolock can be disabled by running
docker swarm update --autolock=false
. After disabling it, the encryption key
is no longer required to start the manager, and it will start up on its own
without user intervention.
--cert-expiry
This flag sets the validity period for node certificates.
--dispatcher-heartbeat
This flag sets the frequency with which nodes are told to use as a period to report their health.
--external-ca
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
The node listens for inbound swarm manager traffic on this address. The default is to listen on
0.0.0.0:2377. It is also possible to specify a network interface to listen on that interface's
address; for example --listen-addr eth0:2377
.
Specifying a port is optional. If the value is a bare IP address or interface name, the default port 2377 will be used.
--advertise-addr
This flag specifies the address that will be advertised to other members of the
swarm for API access and overlay networking. If unspecified, Docker will check
if the system has a single IP address, and use that IP address with the
listening port (see --listen-addr
). If the system has multiple IP addresses,
--advertise-addr
must be specified so that the correct address is chosen for
inter-manager communication and overlay networking.
It is also possible to specify a network interface to advertise that interface's address;
for example --advertise-addr eth0:2377
.
Specifying a port is optional. If the value is a bare IP address or interface name, the default port 2377 will be used.
--task-history-limit
This flag sets up task history retention limit.
--max-snapshots
This flag sets the number of old Raft snapshots to retain in addition to the current Raft snapshots. By default, no old snapshots are retained. This option may be used for debugging, or to store old snapshots of the swarm state for disaster recovery purposes.
--snapshot-interval
This flag specifies how many log entries to allow in between Raft snapshots. Setting this to a higher number will trigger snapshots less frequently. Snapshots compact the Raft log and allow for more efficient transfer of the state to new managers. However, there is a performance cost to taking snapshots frequently.
--availability
This flag specifies the availability of the node at the time the node joins a master.
Possible availability values are active
, pause
, or drain
.
This flag is useful in certain situations. For example, a cluster may want to have
dedicated manager nodes that are not served as worker nodes. This could be achieved
by passing --availability=drain
to docker swarm init
.