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This option allows for testing against Docker containers.

Why?

Using docker as a hypervisor significantly speeds up the provisioning process, as you don't have to spin up an entire VM to run the tests, which has significant overhead.

How?

So first of all, install Docker using the instructions here.

In the real world, it's generally seen as bad practice to have sshd running in a Docker container. However, for the purpose of a disposable test instance, we're not going to worry about that!

Basic docker hosts file

The base image to use for the container is named by the image key.

HOSTS:
  ubuntu-12-10:
    platform: ubuntu-12.10-x64
    image: ubuntu:12.10
    hypervisor: docker
CONFIG:
  type: foss

Docker hosts file, with image modification

You can specify extra commands to be executed in order to modify the image with the keys docker_image_commands and docker_image_first_commands.

docker_image_commands is executed after initial setup. docker_image_first_commands is executed before any other commands and can be used eg. to configure a proxy.

HOSTS:
  ubuntu-12-10:
    platform: ubuntu-12.10-x64
    image: ubuntu:12.10
    hypervisor: docker
    docker_image_first_commands:
      - echo 'Acquire::http::Proxy "http://proxy.example.com:3128";'> /etc/apt/apt.conf.d/01proxy
      - echo "export http_proxy=http://proxy.example.com:3128"> /etc/profile.d/proxy.sh
      - echo "export https_proxy=http://proxy.example.com:3128">> /etc/profile.d/proxy.sh
      - echo "export no_proxy=127.0.0.1,::1">> /etc/profile.d/proxy.sh
    docker_image_commands:
      - 'apt-get install -y myapp'
      - 'myapp --setup'
CONFIG:
  type: foss

Docker hosts files, with modified start commands

By default the docker container just runs an sshd which is adequate for 'puppet apply' style testing. You can specify a different command to start with the docker_cmd key. This gives you scope to run something with more service supervision baked into it, but it is is important that this command starts an sshd listening on port 22 so that beaker can drive the container.

HOSTS:
  ubuntu-12-10:
    platform: ubuntu-12.10-x64
    image: ubuntu:12.10
    hypervisor: docker
    docker_cmd: '["/sbin/init"]'
CONFIG:
  type: foss

Using the entrypoint of an image and not sshd

Instead of using ssh as the CMD for a container, beaker will use the entrypoint already defined if use_image_entry_point is used. Beaker will still load ssh onto the container and start it, but ssh will not be the entrypoint for the container. Below is an example of using the puppetserver image.

HOSTS:
  puppetserver:
    platform: ubuntu-1604-x86_64
    hypervisor: docker
    image: puppet/puppetserver-standalone:6.0.1
    use_image_entry_point: true
    roles:
      - master
CONFIG:
  type: foss

Using dockerfiles with beaker hosts files

Beaker can utilize a dockerfile specified in hosts file; use the dockerfile attribute of a host to specify the location of the dockerfile. Beaker will use the directory it is run in to pass as the context for dockerfile DSL commands such as COPY and VOLUME, so make sure the paths are set correctly for the right context.

HOSTS:
  ubuntu-12-10:
    platform: ubuntu-12.10-x64
    dockerfile: path/to/my/dockerfile
    hypervisor: docker
    docker_cmd: '["/sbin/init"]'
CONFIG:
  type: foss

Preserve Docker Image

Unless the image configuration changes you might want to keep the Docker image for multiple spec runs. Use docker_preserve_image option for a host.

HOSTS:
  ubuntu-12-10:
    platform: ubuntu-12.10-x64
    image: ubuntu:12.10
    hypervisor: docker
    docker_preserve_image: true
CONFIG:
  type: foss

Tag a built Docker Image

Tag an image after creation; this allows for subsequent hosts to reference that image for multi-stage builds.

HOSTS:
  ubuntu-12-10:
    platform: ubuntu-12.10-x64
    dockerfile: path/to/file
    hypervisor: docker
    tag: build_host
  mysecondhost:
    dockerfile: path/to/file # file references build_host
    platform: alpine-3.8-x86_64
    hypervisor: docker
CONFIG:
  type: foss

Reuse Docker Image

In case you want to rerun the puppet again on the docker container, you can pass BEAKER_provision=no on the command line to set the env. Add this line in you default.ml file

HOSTS:
  centos6-64:
    roles:
     - agent
    platform: el-6-x86_64
    image: centos:6.6
    hypervisor: docker
CONFIG:
  type: foss
  log_level: verbose
ssh:
  password: root
  auth_methods: ["password"]

Mounting volumes into your docker container

You can mount folders into a docker container:

HOSTS:
  ubuntu-12-10:
    platform: ubuntu-12.10-x64
    image: ubuntu:12.10
    hypervisor: docker
    mount_folders:
      name1:
        host_path: host_path1
        container_path: container_path1
      name2:
        host_path: host_path2
        container_path: container_path2
        opts: rw
CONFIG:
  type: foss

Example Output

For this example made a new docker nodeset file in the puppetlabs-inifile repo and ran the ini_setting_spec.rb spec:

$ bundle exec rspec spec/acceptance/ini_setting_spec.rb
Hypervisor for debian-7 is docker
Beaker::Hypervisor, found some docker boxes to create
Provisioning docker
provisioning debian-7
Creating image
Dockerfile is         FROM debian:7.4
          RUN apt-get update
          RUN apt-get install -y openssh-server openssh-client curl ntpdate lsb-release
        RUN mkdir -p /var/run/sshd
        RUN echo root:root | chpasswd
RUN apt-get install -yq lsb-release wget net-tools ruby rubygems ruby1.8-dev libaugeas-dev libaugeas-ruby ntpdate locales-all
RUN REALLY_GEM_UPDATE_SYSTEM=1 gem update --system --no-ri --no-rdoc
        EXPOSE 22
        CMD ["/sbin/init"]

This step may take a while, as Docker will have to download the image. The subsequent runs will be a lot faster (as long as docker_preserve_image: true has been enabled).

For example, running this took 5 minutes to download and setup the debian:7.4 image, but runs instantly the second time.

You should then see something like:

Creating container from image 3a86e5aba94d
post
/v1.15/containers/create
{}
{"Image":"3a86e5aba94d","Hostname":"debian-7"}
Starting container b8b31702b34b4aedd137c8a6a72fe730560bb00533e68764ba6263405f9244e4
post
/v1.15/containers/b8b31702b34b4aedd137c8a6a72fe730560bb00533e68764ba6263405f9244e4/start
{}
{"PublishAllPorts":true,"Privileged":true}
Using docker server at 192.168.59.103
get
/v1.15/containers/b8b31702b34b4aedd137c8a6a72fe730560bb00533e68764ba6263405f9244e4/json
{}

node available as  ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no root@192.168.59.103 -p 49155

The tests should then run as normal from there.

Docker-in-Docker (dind)

If you are using docker in docker, set the environment variable DOCKER_IN_DOCKER=true. Beaker-docker will then not try to use the DOCKER_HOST address for the ssh connection to the containers.