docker

Docker Support

Introduction

Docker support for edX services is volatile and experimental. We welcome interested testers and contributors. If you are interested in participating, please join us on Slack at https://openedx.slack.com/messages/docker.

We do not and may never run run these images in production. They are not currently suitable for production use.

Tooling

Dockerfiles for individual services should be placed in docker/build/<service>. There should be an accompanying ansible_overrides.yml which specifies any docker-specific configuration values.

Once the Dockerfile has been created, it can be built and published using a set of make commands.

make docker.build.<service>  # Build the service container (but don't tag it)
                             # By convention, this will build the container using
                             # the currently checked-out configuration repository,
                             # and will build on top of the most-recently available
                             # base container image from dockerhub.

make docker.test.<service>   # Test that the Dockerfile for <service> will build.
                             # This will rebuild any edx-specific containers that
                             # the Dockerfile depends on as well, in case there
                             # are failures as a result of changes to the base image.

make docker.pkg.<service>    # Package <service> for publishing to Dockerhub. This
                             # will also package and tag pre-requisite service containers.

make docker.push.<service>   # Push <service> to Dockerhub as latest.

Image naming

The latest images built from master branches are named edxops/<service>:latest, for example, edxops/edxapp:latest. Images built from Open edX release branches use an appropriate tag, such as edxops/edxapp:hawthorn.master.

Build arguments

Dockerfiles make use of these build arguments:

• OPENEDX_RELEASE is the release branch to use. It defaults to "master". To use an Open edX release, provide the full branch name:

--build-arg OPENEDX_RELEASE=open-release/hawthorn.master

• BASE_IMAGE_TAG is the tag for the base image to build on. It defaults to "latest" for master builds. For an Open edX release, use the name of the release:

--build-arg BASE_IMAGE_TAG=hawthorn.master

Conventions

In order to facilitate development, Dockerfiles should be based on one of the edxops/<ubuntu version>-common base images, and should COPY . /edx/app/edx_ansible/edx_ansible in order to load your local ansible plays into the image. The actual work of configuring the image should be done by executing ansible (rather than explicit steps in the Dockerfile), unless those steps are docker specific. Devstack-specific steps can be tagged with the devstack:install tag in order that they only run when building a devstack image.

The user used in the Dockerfile should be root.