Create a swarm
Estimated reading time: 2 minutesAfter you complete the tutorial setup steps, you’re ready to create a swarm. Make sure the Docker Engine daemon is started on the host machines.
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Open a terminal and ssh into the machine where you want to run your manager node. This tutorial uses a machine named
manager1
. If you use Docker Machine, you can connect to it via SSH using the following command:$ docker-machine ssh manager1
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Run the following command to create a new swarm:
$ docker swarm init --advertise-addr <MANAGER-IP>
Note: If you are using Docker Desktop for Mac or Docker Desktop for Windows to test single-node swarm, simply run
docker swarm init
with no arguments. There is no need to specify--advertise-addr
in this case. To learn more, see the topic on how to Use Docker Desktop or Mac or Docker Desktop for Windows with Swarm.In the tutorial, the following command creates a swarm on the
manager1
machine:$ docker swarm init --advertise-addr 192.168.99.100 Swarm initialized: current node (dxn1zf6l61qsb1josjja83ngz) is now a manager. To add a worker to this swarm, run the following command: docker swarm join \ --token SWMTKN-1-49nj1cmql0jkz5s954yi3oex3nedyz0fb0xx14ie39trti4wxv-8vxv8rssmk743ojnwacrr2e7c \ 192.168.99.100:2377 To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
The
--advertise-addr
flag configures the manager node to publish its address as192.168.99.100
. The other nodes in the swarm must be able to access the manager at the IP address.The output includes the commands to join new nodes to the swarm. Nodes will join as managers or workers depending on the value for the
--token
flag. -
Run
docker info
to view the current state of the swarm:$ docker info Containers: 2 Running: 0 Paused: 0 Stopped: 2 ...snip... Swarm: active NodeID: dxn1zf6l61qsb1josjja83ngz Is Manager: true Managers: 1 Nodes: 1 ...snip...
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Run the
docker node ls
command to view information about nodes:$ docker node ls ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS dxn1zf6l61qsb1josjja83ngz * manager1 Ready Active Leader
The
*
next to the node ID indicates that you’re currently connected on this node.Docker Engine swarm mode automatically names the node for the machine host name. The tutorial covers other columns in later steps.
What’s next?
In the next section of the tutorial, we add two more nodes to the cluster.