DockerCLI/docs/reference/commandline/swarm_join.md

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---
title: "swarm join"
description: "The swarm join command description and usage"
keywords: "swarm, join"
---
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# swarm join
```markdown
Usage: docker swarm join [OPTIONS] HOST:PORT
Join a swarm as a node and/or manager
Options:
--advertise-addr string Advertised address (format: <ip|interface>[:port])
--availability string Availability of the node ("active"|"pause"|"drain") (default "active")
--help Print usage
--listen-addr node-addr Listen address (format: <ip|interface>[:port]) (default 0.0.0.0:2377)
--token string Token for entry into the swarm
```
## Description
Join a node to a swarm. The node joins as a manager node or worker node based upon the token you
pass with the `--token` flag. If you pass a manager token, the node joins as a manager. If you
pass a worker token, the node joins as a worker.
## Examples
### Join a node to swarm as a manager
The example below demonstrates joining a manager node using a manager token.
```bash
Split advertised address from listen address There are currently problems with "swarm init" and "swarm join" when an explicit --listen-addr flag is not provided. swarmkit defaults to finding the IP address associated with the default route, and in cloud setups this is often the wrong choice. Introduce a notion of "advertised address", with the client flag --advertise-addr, and the daemon flag --swarm-default-advertise-addr to provide a default. The default listening address is now 0.0.0.0, but a valid advertised address must be detected or specified. If no explicit advertised address is specified, error out if there is more than one usable candidate IP address on the system. This requires a user to explicitly choose instead of letting swarmkit make the wrong choice. For the purposes of this autodetection, we ignore certain interfaces that are unlikely to be relevant (currently docker*). The user is also required to choose a listen address on swarm init if they specify an explicit advertise address that is a hostname or an IP address that's not local to the system. This is a requirement for overlay networking. Also support specifying interface names to --listen-addr, --advertise-addr, and the daemon flag --swarm-default-advertise-addr. This will fail if the interface has multiple IP addresses (unless it has a single IPv4 address and a single IPv6 address - then we resolve the tie in favor of IPv4). This change also exposes the node's externally-reachable address in docker info, as requested by #24017. Make corresponding API and CLI docs changes. Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2016-06-30 21:07:35 -04:00
$ docker swarm join --token SWMTKN-1-3pu6hszjas19xyp7ghgosyx9k8atbfcr8p2is99znpy26u2lkl-7p73s1dx5in4tatdymyhg9hu2 192.168.99.121:2377
This node joined a swarm as a manager.
$ docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
dkp8vy1dq1kxleu9g4u78tlag * manager2 Ready Active Reachable
dvfxp4zseq4s0rih1selh0d20 manager1 Ready Active Leader
```
A cluster should only have 3-7 managers at most, because a majority of managers must be available
for the cluster to function. Nodes that aren't meant to participate in this management quorum
should join as workers instead. Managers should be stable hosts that have static IP addresses.
### Join a node to swarm as a worker
The example below demonstrates joining a worker node using a worker token.
```bash
Split advertised address from listen address There are currently problems with "swarm init" and "swarm join" when an explicit --listen-addr flag is not provided. swarmkit defaults to finding the IP address associated with the default route, and in cloud setups this is often the wrong choice. Introduce a notion of "advertised address", with the client flag --advertise-addr, and the daemon flag --swarm-default-advertise-addr to provide a default. The default listening address is now 0.0.0.0, but a valid advertised address must be detected or specified. If no explicit advertised address is specified, error out if there is more than one usable candidate IP address on the system. This requires a user to explicitly choose instead of letting swarmkit make the wrong choice. For the purposes of this autodetection, we ignore certain interfaces that are unlikely to be relevant (currently docker*). The user is also required to choose a listen address on swarm init if they specify an explicit advertise address that is a hostname or an IP address that's not local to the system. This is a requirement for overlay networking. Also support specifying interface names to --listen-addr, --advertise-addr, and the daemon flag --swarm-default-advertise-addr. This will fail if the interface has multiple IP addresses (unless it has a single IPv4 address and a single IPv6 address - then we resolve the tie in favor of IPv4). This change also exposes the node's externally-reachable address in docker info, as requested by #24017. Make corresponding API and CLI docs changes. Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2016-06-30 21:07:35 -04:00
$ docker swarm join --token SWMTKN-1-3pu6hszjas19xyp7ghgosyx9k8atbfcr8p2is99znpy26u2lkl-1awxwuwd3z9j1z3puu7rcgdbx 192.168.99.121:2377
This node joined a swarm as a worker.
$ docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
7ln70fl22uw2dvjn2ft53m3q5 worker2 Ready Active
dkp8vy1dq1kxleu9g4u78tlag worker1 Ready Active Reachable
dvfxp4zseq4s0rih1selh0d20 * manager1 Ready Active Leader
```
### `--listen-addr value`
If the node is a manager, it will listen for inbound swarm manager traffic on this
Split advertised address from listen address There are currently problems with "swarm init" and "swarm join" when an explicit --listen-addr flag is not provided. swarmkit defaults to finding the IP address associated with the default route, and in cloud setups this is often the wrong choice. Introduce a notion of "advertised address", with the client flag --advertise-addr, and the daemon flag --swarm-default-advertise-addr to provide a default. The default listening address is now 0.0.0.0, but a valid advertised address must be detected or specified. If no explicit advertised address is specified, error out if there is more than one usable candidate IP address on the system. This requires a user to explicitly choose instead of letting swarmkit make the wrong choice. For the purposes of this autodetection, we ignore certain interfaces that are unlikely to be relevant (currently docker*). The user is also required to choose a listen address on swarm init if they specify an explicit advertise address that is a hostname or an IP address that's not local to the system. This is a requirement for overlay networking. Also support specifying interface names to --listen-addr, --advertise-addr, and the daemon flag --swarm-default-advertise-addr. This will fail if the interface has multiple IP addresses (unless it has a single IPv4 address and a single IPv6 address - then we resolve the tie in favor of IPv4). This change also exposes the node's externally-reachable address in docker info, as requested by #24017. Make corresponding API and CLI docs changes. Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2016-06-30 21:07:35 -04:00
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
Split advertised address from listen address There are currently problems with "swarm init" and "swarm join" when an explicit --listen-addr flag is not provided. swarmkit defaults to finding the IP address associated with the default route, and in cloud setups this is often the wrong choice. Introduce a notion of "advertised address", with the client flag --advertise-addr, and the daemon flag --swarm-default-advertise-addr to provide a default. The default listening address is now 0.0.0.0, but a valid advertised address must be detected or specified. If no explicit advertised address is specified, error out if there is more than one usable candidate IP address on the system. This requires a user to explicitly choose instead of letting swarmkit make the wrong choice. For the purposes of this autodetection, we ignore certain interfaces that are unlikely to be relevant (currently docker*). The user is also required to choose a listen address on swarm init if they specify an explicit advertise address that is a hostname or an IP address that's not local to the system. This is a requirement for overlay networking. Also support specifying interface names to --listen-addr, --advertise-addr, and the daemon flag --swarm-default-advertise-addr. This will fail if the interface has multiple IP addresses (unless it has a single IPv4 address and a single IPv6 address - then we resolve the tie in favor of IPv4). This change also exposes the node's externally-reachable address in docker info, as requested by #24017. Make corresponding API and CLI docs changes. Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2016-06-30 21:07:35 -04:00
name, the default port 2377 will be used.
This flag is generally not necessary when joining an existing swarm.
### `--advertise-addr value`
This flag specifies the address that will be advertised to other members of the
swarm for API access. If unspecified, Docker will check if the system has a
single IP address, and use that IP address with the listening port (see
Split advertised address from listen address There are currently problems with "swarm init" and "swarm join" when an explicit --listen-addr flag is not provided. swarmkit defaults to finding the IP address associated with the default route, and in cloud setups this is often the wrong choice. Introduce a notion of "advertised address", with the client flag --advertise-addr, and the daemon flag --swarm-default-advertise-addr to provide a default. The default listening address is now 0.0.0.0, but a valid advertised address must be detected or specified. If no explicit advertised address is specified, error out if there is more than one usable candidate IP address on the system. This requires a user to explicitly choose instead of letting swarmkit make the wrong choice. For the purposes of this autodetection, we ignore certain interfaces that are unlikely to be relevant (currently docker*). The user is also required to choose a listen address on swarm init if they specify an explicit advertise address that is a hostname or an IP address that's not local to the system. This is a requirement for overlay networking. Also support specifying interface names to --listen-addr, --advertise-addr, and the daemon flag --swarm-default-advertise-addr. This will fail if the interface has multiple IP addresses (unless it has a single IPv4 address and a single IPv6 address - then we resolve the tie in favor of IPv4). This change also exposes the node's externally-reachable address in docker info, as requested by #24017. Make corresponding API and CLI docs changes. Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2016-06-30 21:07:35 -04:00
`--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
Split advertised address from listen address There are currently problems with "swarm init" and "swarm join" when an explicit --listen-addr flag is not provided. swarmkit defaults to finding the IP address associated with the default route, and in cloud setups this is often the wrong choice. Introduce a notion of "advertised address", with the client flag --advertise-addr, and the daemon flag --swarm-default-advertise-addr to provide a default. The default listening address is now 0.0.0.0, but a valid advertised address must be detected or specified. If no explicit advertised address is specified, error out if there is more than one usable candidate IP address on the system. This requires a user to explicitly choose instead of letting swarmkit make the wrong choice. For the purposes of this autodetection, we ignore certain interfaces that are unlikely to be relevant (currently docker*). The user is also required to choose a listen address on swarm init if they specify an explicit advertise address that is a hostname or an IP address that's not local to the system. This is a requirement for overlay networking. Also support specifying interface names to --listen-addr, --advertise-addr, and the daemon flag --swarm-default-advertise-addr. This will fail if the interface has multiple IP addresses (unless it has a single IPv4 address and a single IPv6 address - then we resolve the tie in favor of IPv4). This change also exposes the node's externally-reachable address in docker info, as requested by #24017. Make corresponding API and CLI docs changes. Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2016-06-30 21:07:35 -04:00
name, the default port 2377 will be used.
This flag is generally not necessary when joining an existing swarm.
### `--token string`
Secret value required for nodes to join the swarm
### `--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 join`.
## Related commands
* [swarm init](swarm_init.md)
* [swarm join-token](swarm_join_token.md)
* [swarm leave](swarm_leave.md)
* [swarm unlock](swarm_unlock.md)
* [swarm unlock-key](swarm_unlock_key.md)
* [swarm update](swarm_update.md)