OEP-10: Open edX Releases¶

Components¶

When talking about software that is part of Open edX, there are a number of components that might be useful to discuss, of various sizes:

• Application: this is a user-visible application that provides some useful functionality. Examples are the LMS, Studio, Analytics Insights. These can be composed of a number of different repos and services.
• Service (or IDA): this is a program that can be separately installed and started. Often applications will need a number of these working together to provide all functionality. The LMS and Studio applications are implemented by the edxapp service, which also uses the forums service. A service might or might not have a user interface.
• Feature: large applications have major features which are configurable, and should be called out explicitly if their support status is different than the application they are a part of.

Levels of support¶

Components in Open edX are either included or supported in a release.

To be included in an Open edX release, a component must meet these criteria.

• It must be successfully merged into its repository’s release-from branch. This is typically master, though it can be any branch.
• It must be installable in at least one of the supported installation methods.
• It must be usable in the installed configuration.

Beyond inclusion, to be supported in an Open edX release, a component must meet further criteria:

• It must be documented thoroughly and accurately.
• An engineering team either in edX or outside of edX, must agree to be minimally available for answering questions in the public channels.
• An engineering team either in edX or outside of edX, must agree to provide fixes if severe problems are identified.

Many of these criteria are open to interpretation, or varying degrees of effort. For example, what does “documented thoroughly” mean? We can’t quantify that. It and other loose criteria are included here because they are important parts of providing a finished quality product, and we don’t want to overlook them.

Dependencies¶

Our software is built atop other software layers supported by their creators. It’s important to consider the support windows for those layers when choosing which version to use. An Open edX release is supported by edX until the next release, so for about six months. The supporting layers must be supported by their developers for the entire Open edX release.

Typically this means choosing Long Term Support (LTS) versions of the supporting layers, but it’s possible shorter-term support versions will provide the support needed.

The layers in question here are Django, Python, and Ubuntu. Here’s a calendar of the known support windows and how they overlap with Open edX plans.

Release creation¶

A new release line is created roughly every six months. Release lines are named with words in alphabetical order: Dogwood, Eucalyptus, Ficus, Gingko, and so on. On a release line, there will be a handful of releases: Eucalyptus.1, Eucalyptus.2, and so on.

After the .1 release, new releases in a line are made only for severe problems such as security problems, data loss, or feature breakage.

A new release line is created by making a “release master” branch in each involved repo. These are named “open-release/RELEASENAME.master”. This branch will be where changes are accumulated to create each release in the line. Releases will be tagged “open-release/RELEASENAME.1”, “open-release/RELEASENAME.2”, and so on.

Involving repos in the Open edX build process¶

OEP-2 defines a file format for repository metadata. The openedx-release key is an optional dictionary governing the participation of the repo in the Open edX release process.

openedx-release: dictionary (optional)

Possible keys:

ref

The name of the release-from branch in this repo. This is the branch that will be tagged when an Open edX release is made.

requirements

This key is obsolete, and can be removed.

parent-repo

This key is obsolete. Repos marked with this key should have the entire openedx-release key removed.

Installing Open edX¶

Open edX provides a few supported installation methods, explained below. Currently, none of the supported installation methods are intended for production. Running production servers requires making many choices based on factors such as expected load, budget, and expertise.

Our installations are based on Ansible playbooks. Up until the Eucalyptus release, all supported installation methods were single-machine: all of the Open edX software was installed and ran on a single machine, either a Virtualbox image, or a native machine.

That model does not scale up as the number of services and applications grows. Newer services are supporting Docker for installation. Eventually, we would like the supported installation methods to be based on an all-Docker model where an installation is just a constellation of Docker containers.

To allow us to move gradually from a single-machine model to an all-Docker model, we’ll support a machine running a number of edX services and applications, and also running a number of Docker containers.

Installation methods¶

There are two supported installation methods:

• Devstack: for developers planning to modify Open edX code.
• Native: for adopters looking to experiment with Open edX in a non-production environment. Also useful as a starting point for people designing their production deployment.

The devstack installation will follow OEP-5, with a single-machine Vagrant image running alongside some number of Docker containers.

The native installation will use an Ansible playbook to install Open edX components onto the machine, and install Docker and some number of Docker containers.