Docker Swarm

This project uses Vagrant and Ansible to launch a Docker Swarm Cluster.

It is based on the following tutorial...

Requirements

3 CentOS 7 Virtualbox Instances 2GB RAM / 2 vCPUs.
The 3 nodes will be assigned the following IP addresses 192.168.44.101-103.
192.168.44.101 (cnode1) will be considered the Manager machine.
Docker Swarm is configured but no services are added. An example of how to do that is included below.

git clone https://github.com/rhysmeister/DockerSwarm.git
cd DockerSwarm
vagrant up

vagrant ssh docker1
docker node ls

Create a service called nginx_service, using the nginx image, exposing the port 80.

docker service create --replicas 5 -p 80:80 --name nginx_service nginx

View the containers in the Swarm

docker service ps nginx_service

Ensure what all three Swarm nodes return the Welcome to nginx message

ips="192.168.44.101 192.168.44.102 192.168.44.103"
for ip in "$ips"; do  curl -s http://$ip | grep --color "<h1>Welcome to nginx"; done

Remove the service

docker service rm nginx_service

Lock the Swarm

docker swarm update --autolock=true

Take a note of the Swarm key the restart the service

systemctl restart docker

Then

docker node ls

Error response from daemon: Swarm is encrypted and needs to be unlocked before it can be used. Please use "docker swarm unlock" to unlock it.

Unlock the cluster (need to provide the swarm key when prompted)

docker swarm unlock

Then...

docker node ls