609c7c0bcb
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>
Upstream-commit: 18cd5ac352
Component: cli
3.7 KiB
swarm join
Usage: docker swarm join [OPTIONS] HOST:PORT
Join a swarm as a node and/or manager
Options:
--advertise-addr value Advertised address (format: <ip|hostname|interface>[:port])
--help Print usage
--listen-addr value Listen address
--token string Token for entry into the swarm
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.
Join a node to swarm as a manager
The example below demonstrates joining a manager node using a manager token.
$ 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.
$ 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
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, hostname, or interface 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 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, hostname, or interface name, the default port 2377 will be used.
This flag is generally not necessary when joining an existing swarm.
--manager
Joins the node as a manager
22565e1... Split advertised address from listen address
--token string
Secret value required for nodes to join the swarm