Initialise Docker Swarm with: $ docker swarm init --advertise-addr <MANAGER_IP>
If you are using a Mac or Windows PC with Docker Desktop you can omit the --advertise-addr flag.
$ docker swarm init --advertise-addr 192.168.65.3
Swarm initialized: current node (sa6c5bgy7tuuvtee2prvt5141) is now a manager.
To add a worker to this swarm, run the following command:
docker swarm join --token SWMTKN-1-5cqlf1vko17n16xc8x5v633ltdjr6xtilp26nw7d9avyxhfin6-1xinuuayy7hd8f75sar3zmaz8 192.168.65.3:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions. Since Docker Swarm will run on multiple Docker Hosts it is mandatory that your container images are available in a container registry. You can e.g. push them to quay.io or Docker Hub.
If you just want to try out docker swarm, then feel free to create a "throwaway container registry" locally. You can do so by executing:
$ docker service create --name registry --publish published=5000,target=5000 registry:2
ujf26qwx67juj1ni5dyma2o8l
overall progress: 1 out of 1 tasks
1/1: running
verify: Service converged
$ docker service ls
ID NAME MODE REPLICAS IMAGE PORTS
ujf26qwx67ju registry replicated 1/1 registry:2 *:5000->5000/tcpBefore you deploy your swarm, make shure your application is working like expected. To do so, simply start it with docker-compose.
$ docker-compose up -d
WARNING: The Docker Engine you\'re using is running in swarm mode.
Compose does not use swarm mode to deploy services to multiple nodes in a swarm. All containers will be scheduled on the current node.
To deploy your application across the swarm, use `docker stack deploy`.
Creating network "docker-swarm-example_default" with the default driver
Creating volume "docker-swarm-example_data" with default driver
Creating docker-swarm-example_web_1 ... done
Creating docker-swarm-example_visualizer_1 ... done
Creating docker-swarm-example_redis_1 ... doneCheck if all services are running:
$ docker-compose ps
Name Command State Ports
---------------------------------------------------------------------------------------------------
docker-swarm-example_redis_1 docker-entrypoint.sh redis ... Up 0.0.0.0:6379->6379/tcp
docker-swarm-example_visualizer_1 npm start Up 0.0.0.0:8080->8080/tcp
docker-swarm-example_web_1 python app.py Up 0.0.0.0:8000->8000/tcpThen stop your application
$ docker-compose down --volumes
Stopping docker-swarm-example_redis_1 ... done
Stopping docker-swarm-example_visualizer_1 ... done
Stopping docker-swarm-example_web_1 ... done
Removing docker-swarm-example_redis_1 ... done
Removing docker-swarm-example_visualizer_1 ... done
Removing docker-swarm-example_web_1 ... done
Removing network docker-swarm-example_default
Removing volume docker-swarm-example_dataAnd push the images to the registry with
$ docker-compose push
Pushing web (127.0.0.1:5000/stackdemo:latest)...
The push refers to repository [127.0.0.1:5000/stackdemo]
2b26e33b602b: Pushed
df9e12995dc3: Pushed
d63fdf4f6b3d: Pushed
11210af4e885: Pushed
178572d98447: Pushed
61b675163d2a: Pushed
5216338b40a7: Pushed
latest: digest: sha256:95edea2d6eaaaa66b4eb705c64b76fd3e293cee88b1175928e83353f1ff92eb5 size: 1788Use the docker-compose.yml to deploy your application with docker swarm. All instructions that are not supported by docker swarm (like build) will automatically be ignored.
$ docker stack deploy --compose-file docker-compose.yml stackdemo
Ignoring unsupported options: build
Creating network stackdemo_default
Creating service stackdemo_web
Creating service stackdemo_redis
Creating service stackdemo_visualizerYou can view all of of the services running with:
$ docker stack services stackdemo
ID NAME MODE REPLICAS IMAGE PORTS
kebocx1hvtmk stackdemo_redis replicated 1/1 redis:alpine *:6379->6379/tcp
vmtjfjv8ymj9 stackdemo_web replicated 2/2 127.0.0.1:5000/stackdemo:latest *:8000->8000/tcp
wikio3xzeoyb stackdemo_visualizer replicated 1/1 dockersamples/visualizer:stable *:8080->8080/tcpIf you wish to scale a service, simply do:
$ docker service scale <SERVICE>=<REPLICAS>For Example:
$ docker service scale stackdemo_web=5
stackdemo_web scaled to 5
overall progress: 5 out of 5 tasks
1/5: running [==================================================>]
2/5: running [==================================================>]
3/5: running [==================================================>]
4/5: running [==================================================>]
5/5: running [==================================================>]
verify: Service convergedIf you know do another $ docker stack services stackdemo, you should see:
$ docker stack services stackdemo
ID NAME MODE REPLICAS IMAGE PORTS
kebocx1hvtmk stackdemo_redis replicated 1/1 redis:alpine *:6379->6379/tcp
vmtjfjv8ymj9 stackdemo_web replicated 5/5 127.0.0.1:5000/stackdemo:latest *:8000->8000/tcp
wikio3xzeoyb stackdemo_visualizer replicated 1/1 dockersamples/visualizer:stable *:8080->8080/tcpA visualization of the whole cluster is provided under http://localhost:8080.
Just use the command provided when you initialized the cluster to join other nodes to the cluster.
$ docker swarm join --token SWMTKN-1-5cqlf1vko17n16xc8x5v633ltdjr6xtilp26nw7d9avyxhfin6-1xinuuayy7hd8f75sar3zmaz8 192.168.65.3:2377
This node joined s swarm as a worker To check if everything worked as expected:
$ docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION
sdp8vy1dq1kxleu9g4u78tlag * worker1 Ready Active Reachable ...
sa6c5bgy7tuuvtee2prvt5141 * manager1 Ready Active Leader ...If you wish to show the join command again, docker provides a useful built-in command. Simply execute:
# join command for a new manager node
$ docker swarm join-token manager
# join command for a new worker node
$ docker swarm join-token workerIf you want to test multi-node docker swarm on a single machine, you can use docker machine.
Docker Machine allow you to create multiple virtual docker hosts on your machine. You can create one using:
- Mac: $ docker-machine create --driver virtualbox default
- Windows: $ docker-machine create --driver hyperv default
- Linux: $ docker-machine create --driver amazonec2 default
(Linux actually provides a handful of different drivers incl. Amazon Web Services, Microsoft Azure, Digital Ocean, Google Compute Engine and OpenStack )
Then use $ eval ”$(docker-machine env default)” to switch you current shell to the created docker host.
$ curl http://localhost:8000
Hello World! I have been seen 1 times.
$ curl http://localhost:8000
Hello World! I have been seen 2 times.
$ curl http://localhost:8000
Hello World! I have been seen 3 times.Remove your stack with:
$ docker stack rm stackdemo
Removing service stackdemo_redis
Removing service stackdemo_visualizer
Removing service stackdemo_web
Removing network stackdemo_defaultIn case you create a throwaway local registry, you can remove it with:
$ docker service rm registry
registry$ docker swarm leave --force
Node left the swarm.