08_swarm.md

Setup swarm cluster

master

Prerequisities

• Delete previously create vm default
• Create VM instances using docker-machine
  • master
  • node-01
  • node-02

Create swarm master node

Connect to docker on master node and initialize swarm master with command

docker swarm init --advertise-addr <MASTER_IP>

Then follow the instructions to join nodes (node-01 and node-02) to swarm cluster.

Create network called net-apps with driver overlay.

Verify that swarm is successfully deployed

eval $(docker-machine env master)

docker info

docker node ls

Label nodes with custom labels

Node name	label
master	purpose=master
node-01	purpose=worker
node-02	purpose=worker

Hint: Use docker node --help

Test failover

Run single service on redis on worker node with label worker

docker service create --constraint node.labels.purpose==worker --name=redis --network=net-apps redis

Find out on which node is redis running and stop docker service on that node.

Verify that container started on new node.

Scheduling

• use docker constraints to run container based on newly defined label,
• use container affinity to create container on the same node with previously started container.

Run app stack on swarm cluster

Use your compose file to deploy applications to nodes in swarm cluster. Don't forget to delete all previously created app containers.