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Puppet module for installing, configuring and managing Docker from the official repository on Ubuntu, from EPEL on RedHat based distributions or the standard repositories for Archlinux and Fedora.

This module is currently tested on:

• Ubuntu 12.04
• Ubuntu 14.04
• Centos 7.0

It may work on other distros and additional operating systems will be supported in the future. It's definitely been used with the following too:

• Centos 6.5
• Archlinux
• Amazon Linux
• Fedora

The module includes a single class:

include 'docker'

By default this sets up the docker hosted repository if necessary for your OS and installs the docker package and on Ubuntu, any required Kernel extensions.

If you don't want this module to mess about with your Kernel then you can disable this feature like so. It is only enabled (and supported) by default on Ubuntu:

class { 'docker':
  manage_kernel => false,
}

If you want to configure your package sources independently, inform this module to not auto-include upstream sources (This is already disabled on Archlinux as there is no further upstream):

class { 'docker':
  use_upstream_package_source => false,
}

By default the docker daemon will bind to a unix socket at /var/run/docker.sock. This can be changed, as well as binding to a tcp socket if required.

class { 'docker':
  tcp_bind    => 'tcp://127.0.0.1:4243',
  socket_bind => 'unix:///var/run/docker.sock',
}

Unless specified this installs the latest version of docker from the docker inc repository on first run. However if you want to specify a specific version you can do so, unless you are using Archlinux which only supports the latest release:

class { 'docker':
  version => '0.5.5',
}

And if you want to track the latest version you can do so:

class { 'docker':
  version => 'latest',
}

In some cases dns resolution won't work well in the container unless you give a dns server to the docker daemon like this:

class { 'docker':
  dns => '8.8.8.8',
}

The class contains lots of other options, please see the inline code documentation for the full options.

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 { 'base': }

This is equivalent to running docker pull base. 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 exec. Takes an optional parameter for installing image tags that is the equivalent to running docker pull -t="precise" ubuntu:

docker::image { 'ubuntu':
  image_tag => 'precise'
}

Note: images will only install if an image of that name does not already exist.

A images can also be added/build from a dockerfile with the docker_file property, this equivalent to running docker build -t ubuntu - < /tmp/Dockerfile

docker::image { 'ubuntu':
  docker_file => '/tmp/Dockerfile'
}

Images can also be added/build from a directory containing a dockerfile with the docker_dir property, this is equivalent to running docker build -t ubuntu /tmp/ubuntu_image

docker::image { 'ubuntu':
  docker_dir => '/tmp/ubuntu_image'
}

You can also remove images you no longer need with:

docker::image { 'base':
  ensure => 'absent'
}

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

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

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

This is equivalent to running the following under upstart:

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

Run also contains a number of optional parameters:

docker::run { 'helloworld':
  image           => 'base',
  command         => '/bin/sh -c "while true; do echo hello world; sleep 1; done"',
  ports           => ['4444', '4555'],
  expose          => ['4666', '4777'],
  links           => ['mysql:db'],
  use_name        => true,
  volumes         => ['/var/lib/couchdb', '/var/log'],
  volumes_from    => '6446ea52fbc9',
  memory_limit    => 10m, # (format: <number><unit>, where unit = b, k, m or g)
  cpuset          => ['0', '3'],
  username        => 'example',
  hostname        => 'example.com',
  env             => ['FOO=BAR', 'FOO2=BAR2'],
  dns             => ['8.8.8.8', '8.8.4.4'],
  restart_service => true,
  privileged      => false,
  pull_on_start   => false,
  depends         => [ 'container_a', 'postgres' ],
}

Ports, expose, env, dns and volumes can be set with either a single string or as above with an array of values.

Specifying pull_on_start will pull the image before each time it is started.

The depends option allows expressing containers that must be started before. This affects the generation of the init.d/systemd script.

The service file created for systemd and upstart based systems enables automatic restarting of the service on failure by default.

To use an image tag just append the tag name to the image name separated by a semicolon:

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

Docker also supports running arbitrary comments within the context of a running container. And now so does the Puppet module.

docker::exec { 'helloworld-uptime':
  detached  => true,
  container => 'helloworld',
  command   => 'uptime',
  tty       => true,
}