Use Puppet in Docker

Requirements

To use this guide you’ll need a working installation of Puppet from Puppet Labs .

The module also currently uses the official PPA so only works with Ubuntu.

Installation

The module is available on the Puppet Forge and can be installed using the built-in module tool.

$ puppet module install garethr/docker

It can also be found on GitHub if you would rather download the source.

Usage

The module provides a puppet class for installing Docker and two defined types for managing images and containers.

Installation

include 'docker'

Images

The next step is probably to install a Docker image. For this, we have a defined type which can be used like so:

docker::image { 'ubuntu': }

This is equivalent to running:

$ docker pull ubuntu

Note that it will only be downloaded if an image of that name does not already exist. This is downloading a large binary so on first run can take a while. For that reason this define turns off the default 5 minute timeout for the exec type. Note that you can also remove images you no longer need with:

docker::image { 'ubuntu':
  ensure => 'absent',
}

Containers

Now you have an image where you can run commands within a container managed by Docker.

docker::run { 'helloworld':
  image   => 'ubuntu',
  command => '/bin/sh -c "while true; do echo hello world; sleep 1; done"',
}

This is equivalent to running the following command, but under upstart:

$ docker run -d ubuntu /bin/sh -c "while true; do echo hello world; sleep 1; done"

Run also contains a number of optional parameters:

docker::run { 'helloworld':
  image        => 'ubuntu',
  command      => '/bin/sh -c "while true; do echo hello world; sleep 1; done"',
  ports        => ['4444', '4555'],
  volumes      => ['/var/lib/couchdb', '/var/log'],
  volumes_from => '6446ea52fbc9',
  memory_limit => 10485760, # bytes
  username     => 'example',
  hostname     => 'example.com',
  env          => ['FOO=BAR', 'FOO2=BAR2'],
  dns          => ['8.8.8.8', '8.8.4.4'],
}