The Docker Official Repositories are a curated set of Docker repositories that are promoted on Docker Hub. They are designed to:
Provide essential base OS repositories (for example, ubuntu, centos) that serve as the starting point for the majority of users.
Provide drop-in solutions for popular programming language runtimes, data stores, and other services, similar to what a Platform-as-a-Service (PAAS) would offer.
Exemplify Dockerfile best practices and provide clear documentation to serve as a reference for other Dockerfile authors.
Ensure that security updates are applied in a timely manner. This is particularly important as many Official Repositories are some of the most popular on Docker Hub.
Provide a channel for software vendors to redistribute up-to-date and supported versions of their products. Organization accounts on Docker Hub can also serve this purpose, without the careful review or restrictions on what can be published.
Docker, Inc. sponsors a dedicated team that is responsible for reviewing and publishing all Official Repositories content. This team works in collaboration with upstream software maintainers, security experts, and the broader Docker community.
While it is preferable to have upstream software authors maintaining their corresponding Official Repositories, this is not a strict requirement. Creating and maintaining images for Official Repositories is a public process. It takes place openly on GitHub where participation is encouraged. Anyone can provide feedback, contribute code, suggest process changes, or even propose a new Official Repository.
New Docker users are encouraged to use the Official Repositories in their projects. These repositories have clear documentation, promote best practices, and are designed for the most common use cases. Advanced users are encouraged to review the Official Repositories as part of their Dockerfile learning process.
A common rationale for diverging from Official Repositories is to optimize for image size. For instance, many of the programming language stack images contain a complete build toolchain to support installation of modules that depend on optimized code. An advanced user could build a custom image with just the necessary pre-compiled libraries to save space.
A number of language stacks such as python and ruby have -slim tag variants designed to fill the need for optimization. Even when these “slim” variants are insufficient, it is still recommended to inherit from an Official Repository base OS image to leverage the ongoing maintenance work, rather than duplicating these efforts.
All Official Repositories contain a User Feedback section in their documentation which covers the details for that specific repository. In most cases, the GitHub repository which contains the Dockerfiles for an Official Repository also has an active issue tracker. General feedback and support questions should be directed to #docker-library on Freenode IRC.
From a high level, an Official Repository starts out as a proposal in the form of a set of GitHub pull requests. You'll find detailed and objective proposal requirements in the following GitHub repositories:
The Official Repositories team, with help from community contributors, formally review each proposal and provide feedback to the author. This initial review process may require a bit of back and forth before the proposal is accepted.
There are also subjective considerations during the review process. These subjective concerns boil down to the basic question: “is this image generally useful?” For example, the python Official Repository is “generally useful” to the large Python developer community, whereas an obscure text adventure game written in Python last week is not.
When a new proposal is accepted, the author becomes responsible for keeping their images up-to-date and responding to user feedback. The Official Repositories team becomes responsible for publishing the images and documentation on Docker Hub. Updates to the Official Repository follow the same pull request process, though with less review. The Official Repositories team ultimately acts as a gatekeeper for all changes, which helps mitigate the risk of quality and security issues from being introduced.
Note: If you are interested in proposing an Official Repository, but would like to discuss it with Docker, Inc. privately first, please send your inquiries to partners@docker.com. There is no fast-track or pay-for-status option.