Swarm Cluster on AWS with Docker 1.12

Docker 1.12 contains some significant changes to how Swarm cluster are created, managed and used. Quickly put, Swarm is now embedded in the Docker engine and provides some advanced networking features like load-balancing and virtual IPs for services.

This playbook is meant as a quick way to test Docker 1.12 RC2 for #dockercon.

The main playbook creates a cluster of Ubuntu 15.10 machines on AWS. Then you can bootstrap those machines to create a Swarm cluster with the new Docker 1.12

Start the cluster

Check the content of the main play and run it. It will create a SSH key pair and a swarm security group for you.

$ ansible-playbook swarm.yml

Check the inventory file and after a bit of time, you should have Docker running everywhere:

$ ansible swarm -m shell -a "sudo docker ps"
52.208.57.134 | SUCCESS | rc=0 >>
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

52.51.96.89 | SUCCESS | rc=0 >>
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

head | SUCCESS | rc=0 >>
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

52.30.66.217 | SUCCESS | rc=0 >>
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

Install Docker 1.12 on all your nodes

This play downloads the tarball of 1.12 and replaces the existing Docker it is a bit hackish (to say the least). Note that 1.12 is still in RC state.

$ ansible-playbook bootstrap.yml

After a short time, you should get back on your feet with Docker 1.12 on all your nodes

$ ansible swarm -b -m shell -a "docker version | grep Version"
 Version:      1.12.0-rc2
 Version:      1.12.0-rc2
 Version:      1.12.0-rc2
 Version:      1.12.0-rc2
 Version:      1.12.0-rc2
 Version:      1.12.0-rc2
 Version:      1.12.0-rc2
 Version:      1.12.0-rc2

Create your Swarm

Initialize your Swarm head

$ ansible head -b -m shell -a "docker swarm init"

Join the nodes in your Swarm cluster, note that we only run this on the nodes defined in the inventory. Get the private IP of the head node from the inventory (because the security group is not wide open...)

$ ansible nodes -b -m shell -a "docker swarm join <PRIVATE_IP_HEAD>:2377"

Test it

$ ansible head -m shell -b -a "docker node list"

Now use it

On the head node create a service

$ docker service create --name game --publish 80:80 --replicas 4 runseb/2048
2xia8q3b6io1nbb946g95zh00

You will see it listed

$ sudo docker service ls
ID            NAME  REPLICAS  IMAGE        COMMAND
2xia8q3b6io1  game  4/4       runseb/2048  

And a service is made of tasks that are individual containers.

$ docker service tasks game
ID                         NAME    SERVICE  IMAGE        LAST STATE              DESIRED STATE  NODE
4tceqzyflwiz0f88kxq9dlqsz  game.1  game     runseb/2048  Running About a minute  Running        ip-172-31-0-198
58grjto24nx5dqtqicp21mtbd  game.2  game     runseb/2048  Running About a minute  Running        ip-172-31-13-247
5lh0wfhw5mqnhodcszomjit37  game.3  game     runseb/2048  Running About a minute  Running        ip-172-31-13-248
2y6zuue6v67elzfxpxf2uo41l  game.4  game     runseb/2048  Running About a minute  Running        ip-172-31-13-248