docker.md

• Docker integration
  • Docker for testing
  • Building Docker images
    • Using tp build (WIP)
    • Using tp::rocker (WIP)
    • Using image_clone (TODO)
  • General maintenance
    • Docker status
    • Docker files cleanup
  • Docker prerequisites

Docker integration

This control-repo provides various ways to use, configure and work with Docker.

They are available via shell commands, we are going to show them both.

Docker for testing

We can try to test a Puppet run for a role in a Docker container.

To run Puppet for the default docker_test_role on the default image (centos-7):

bin/docker_test_role.sh

To test another role (define the profiles to use and the relevant data in hieradata/role/$role.yaml

bin/docker_test_role.sh ansible

It's also possible to select the underlying OS to use in the base image:

Available images are: ubuntu-12.04, ubuntu-14.04, ubuntu-16.04, centos-7, debian-7, debian-8, alpine-3.3.

bin/docker_test_role.sh myrole debian-8

NOTE: the base images used for the different OS are by default downloaded from https://hub.docker.com/r/example42/puppet-agent/tags/.

It's possible to use custom ones by:

• Setting on Hiera in the "role".yaml files the parameter docker::username (example42 by default)
• Build custom puppet-agent images
• Push them to our registry for use outside our local machine

Building Docker images

In this control-repo various ways to use Puppet to build Docker images are explored.

They follow different approaches and have their own limitations. Work is progress (WIP) here.

Using tp build (WIP)

Dockerize a role entirely based on tp defines for one or multiple OS Docker images.

In this approach, Puppet is executed on our local machine, we might need root privileges to set file permissions.

bin/docker_tp_build_role.sh 

The above command uses the data in hieradata/role/docker_tp_build.yaml

To specify a different role to build for:

bin/docker_tp_build_role.sh webserver

Using tp::rocker (WIP)

To build an image with Rocker, without leaving traces of Puppet inside the image, we can run the following command.

Data used for the image is in hieradata/role/$puppetrole.yaml

docker.rocker_build_role

Using image_clone (TODO)

General maintenance

A few other commands are available for general Docker maintenance.

Docker status

To show general Docker information (version, containers and images):

bin/docker_status.sh

Docker files cleanup

To remove all local images and containers (WARNING: have no important data there).

By default a confirmation prompt appears:

bin/docker_purge.sh

To run in unattended mode (useful for cleanups in CI pipelines):

bin/docker_purge.sh auto

Docker prerequisites

Docker operations the command line require Docker to be locally installed.

If we use Mac or Windows we need the newer native client.

To install docker we can run one of these commands:

bin/docker_setup.sh

You'll need to run docker login before trying any operation that involves pushing our images to Docker registry.