Rancher Swarm

A simple tutorial on how to make a Docker swarm cluster on top of Vagrant.

For this you need at least 3 GB of ram free on your computer. This might work with less if you change the ram levels, but just have at least 3 GB of ram free just in case.

How to cluster

First, you need the machines to cluster:

$ vagrant up

Now, you need a docker swarm discovery token:

$ docker run --rm swarm create
fd243153d366c4fc088de73681b884ad

First you'll need to get the first runner online and waiting in the cluster.

$ vagrant ssh runner-01
runner-01$ sudo ros c set user_docker.args '[docker, -d, -s, overlay, -G, docker, -H, unix:///var/run/docker.sock, -H, tcp://0.0.0.0:2375]'
runner-01$ sudo system-docker restart docker

Now have that machine join the cluster:

runner-01$ docker run --name swarm -d swarm join --addr=172.19.8.101:2375 token://fd243153d366c4fc088de73681b884ad

Repeat this for the other two nodes.

Now connect to the management vm:

$ vagrant ssh manager
manager$ docker run -d -p 2375:2375 swarm manage token://fd243153d366c4fc088de73681b884ad

You now have a working cluster. Now to prove it:

$ docker -H tcp://172.19.8.104:2375 info
Containers: 3
Images: 3
Role: primary
Strategy: spread
Filters: affinity, health, constraint, port, dependency
Nodes: 3
 runner-01: 172.19.8.101:2375
  └ Containers: 1
  └ Reserved CPUs: 0 / 1
  └ Reserved Memory: 0 B / 1.025 GiB
  └ Labels: executiondriver=native-0.2, kernelversion=3.19.8-ckt1-rancher, operatingsystem=<unknown>, storagedriver=overlay
 runner-02: 172.19.8.102:2375
  └ Containers: 1
  └ Reserved CPUs: 0 / 1
  └ Reserved Memory: 0 B / 1.025 GiB
  └ Labels: executiondriver=native-0.2, kernelversion=3.19.8-ckt1-rancher, operatingsystem=<unknown>, storagedriver=overlay
 runner-03: 172.19.8.103:2375
  └ Containers: 1
  └ Reserved CPUs: 0 / 1
  └ Reserved Memory: 0 B / 1.025 GiB
  └ Labels: executiondriver=native-0.2, kernelversion=3.19.8-ckt1-rancher, operatingsystem=<unknown>, storagedriver=overlay
CPUs: 3
Total Memory: 3.075 GiB
Name: 66d026cc952c

You may need to unset DOCKER_TLS_VERIFY depending on your configuration.

Now you have a working docker swarm!