This page is about contributing to the development of Ubuntu itself. If you are interested in developing applications for Ubuntu, see the Ubuntu Developer site.
Overview of Development
Ubuntu is developed by a team of UbuntuDevelopers.
This process is transparent to the public, and open to any contributor who demonstrates the necessary skills and commitment to the project.
Ubuntu is periodically released according to a set schedule.
Like most operating systems, Ubuntu is complex, and it can help to get a broad overview of its architecture first. For that, see UbuntuArchitecture.
If you have been directed to this page for advice on contributing to Ubuntu as a developer, you may also be interested in ContributeToUbuntu.
Working with Other Developers
You are not alone! Ubuntu is the work of many developers, and we devote some effort to enabling efficient collaboration with tools, infrastructure, government and a cooperative spirit.
UbuntuDevelopers explains the roles of developers in the Ubuntu project and how to join the teams.
If you are brand new to Ubuntu Development and need to install the development tool set, or need step by step reminder on how to, check out the Ubuntu Beginner Developers' Tools Installation Quick Start
If you already have experience working with Debian packages, most of your knowledge applies equally well to Ubuntu packaging. If you are a Debian developer, UbuntuForDebianDevelopers summarizes some of the differences between the projects, and later sections in this document provide details of our infrastructure.
To submit patches for review or to help reviewing patches, please refer to the Code Review process.
To find the developer responsible for the component you're working on, see DeveloperResponsibilities.
Email discussion among Ubuntu developers takes place on the ubuntu-devel mailing list, which is moderated (excepting registered Ubuntu developers). The ubuntu-devel-discuss mailing list is available for open discussion about Ubuntu development (not for reporting bugs or user support). All UbuntuDevelopers should subscribe to the ubuntu-devel-announce mailing list, where important development events are announced. Various other mailing lists are available, some of which focus on specific areas of development.
The #ubuntu-devel channel on the FreeNode IRC network is home to many Ubuntu developers for real-time communication.
Automated notifications of development activity are also useful for keeping up with what other developers are working on.
A comprehensive matrix of communication channels can be found on DeveloperCommunication.
Bugs and the BugSquad
Ubuntu bug reports are tracked in Launchpad. HelpingWithBugs contains information about how they are handled. The BugSquad documentation describes how to cooperate with other developers and volunteers working on bug triage; it is required reading for new developers, as developers will typically need to spend a significant amount of time working with the bug tracking system.
The BugSquad (and the Ubuntu Bug Control team, which is comprised of more experienced triagers who can prioritize bugs) are here to help you as a developer. If you are responsible for a non-trivial number of bugs, it is a good idea to spend some time on helping them help you. A useful starting point is to add specific information about your packages to DebuggingProcedures: this may include both special tricks for debugging them effectively and any particular policy you have on how you want your bugs to be handled (e.g. assignment, tags, etc.). When adding significant chunks of new information to DebuggingProcedures, please send a note to email@example.com about it.
Papercuts are fast to fix, but annoying bugs.
Release Critical bugs
RCBugTargetting documents the intended use of the various facilities of the bug tracking system to track release-critical bugs.
Showstopper bugs Critical and milestoned to the relevant release. Those bugs will hold up the release if not fixed.
Release-critical bugs Critical and high importance bugs milestoned to the relevant release. Those bugs need to be fixed or worked around/documented before the release.
In particular, if you make a temporary change to a package for whatever reason which should be reverted before release, please file a release-critical bug about it so that this can be tracked by the release team.
The Release Process
Ubuntu does time-based releases. The Release Process section covers all the release management steps such as beginning a new release, planning it, merging with upstream, feature development, stabilization and freezes, milestone, finalization and stable releases.
Working with Debian-format Packages
Ubuntu uses the Debian packaging format. The following resources explain how to create and modify Debian-format packages.
If you are already familiar with Debian development, UbuntuForDebianDevelopers explains some of the differences between the projects.
All Ubuntu developers should be familiar with the Debian New Maintainer Guide; though be aware that there are many differences (technical, social and procedural) between Ubuntu and Debian of which they must also be aware.
Many packages use tools to help manage multiple patches. Patching Ubuntu packages explains how to work with them.
The CDBS Manual explains how to work with packages using the CDBS packaging scripts, one example of a patch system (and more)
Packaging shared libraries is a delicate task, and getting it wrong can cause upgrade headaches for users. The Debian Library Packaging Guide can be useful in avoiding some of the common traps.
For a deeper understanding of the packaging process, you might want to have a look at this one: http://wiki.debian.org/Courses2005/BuildingWithoutHelper
http://people.debian.org/~calvin/unofficial/ contains information on maintaining your own archive of unofficial packages.
how to write watch files for sourceforge.net hosted projects
Working with Ubuntu Packages
Set the target suite in debian/changelog to be the code name of the current development branch, e.g. "dch -D raring"
When working with a package which originated in Debian, use a version number derived from the Debian version number with ubuntu<revision> appended. e.g. Debian 1.0-2 becomes 1.0-2ubuntu1, followed by 1.0-2ubuntu2, etc.
When fixing a bug tracked in Launchpad, be sure to insert LP: #xxxxxx notation in your changelog entry, for example:
mypackage (2.2-2) raring; urgency=low * hello(1) now prints "Hello, world!" instead of "Hello yourself." (LP: #500000) -- A. Developer <firstname.lastname@example.org> Mon, 17 Dec 2007 18:27:50 +0000Note: The regex in Launchpad looks for LP: #xxxxxx at a minimum. The preferred form is (LP: #xxxxxx).
- When creating a new package which may later be added to Debian, use a revision of the form -0ubuntu1
Remember to include the orig.tar.gz if this is a new upstream version of a non-native package but you have already patched it before upload. A missing original tarball may cause the upload to be rejected or silently dropped. Use dpkg-buildpackage -S -sa to generate such an upload. If the orig.tar.gz is already in the distribution then you don't need to upload it again.
Always be aware of the release schedule and any applicable freezes. The cooperation of all developers is needed in order to ensure a successful release!
- If your changes may affect the work of other developers, it is a good idea to discuss them on a mailing list first
For merging a Ubuntu package with a newer Debian version, see /Merging
Revision control (Bazaar)
Bazaar, an open source revision control system and Canonical sponsored project, is the preferred revision control system in Ubuntu. Many Ubuntu packages are maintained in Bazaar, which makes it easy for other developers to contribute changes to them, which can be easily merged by the maintainer.
Note that, as a practical matter, many packages are not yet maintained in Bazaar, but in other revision control systems or none on a case-by-case basis. (Work is underway to rectify this.) Where no revision control system is used, the history of uploads recorded in Launchpad may be useful.
Ubuntu Flavors and Derivative Distributions
The Ubuntu project produces several distributions each release cycle. These are sometimes called "flavours". Kubuntu, Edubuntu, and Xubuntu are all maintained directly in the Ubuntu archive. There are also a large number of derivative distributions that are based on the Ubuntu archive, but separately developed.
"Upstream" is the term used to describe all the places where Ubuntu pulls its software from. The developers of this software write it and then it flows downstream in to Ubuntu and then in to its derivatives.
See http://distributions.freedesktop.org/wiki/Packaging/WhyUpstream for why upstream is so important, and some tips on working with upstream to improve the software, and hence Ubuntu.
There is one upstream that is critical to Ubuntu, Debian. This is where most of the packages in Ubuntu come from, and so working with them is important.
You should always build and test packages locally before submitting them to Ubuntu. Failure to do so will waste the time of other members of the community, so please be considerate.
Backports are explained at UbuntuBackports
The process for either requesting a new package or getting your own new package included in Ubuntu is described at UbuntuDevelopment/NewPackages.
The Package Archive
All current official Ubuntu packages are stored in the master archive, which is widely mirrored. It is administered by the archive administration team. The Packaging Archive section covers details such as the processes of interaction with the build daemons and the archive. It also explains how different architectures and package components are handled and how the autobuilders work.
The Installation media section discusses the different supported installation media types, how to obtain them and contains pointers to Installer development.
Language packs - Internationalisation / Localisation
Unlike other distributions we do not ship upstream translations from source packages directly in binary application packages in main and restricted, since this does not allow us any flexibility in editing them on a central place (Launchpad), update them independently from the applications, and update them post release. That is why we separate packages and their translations in Ubuntu and maintain/package them independently.
The complete lifecycle of translations (import, maintenance, export, and language pack structure) is described on TranslationLifecycle.
The main article is at Internationalisation Guide for Developers
These resources should be incorporated into new or existing sections elsewhere in this document, but are temporarily recorded here so that we remember to come back to them later:
Debian Python Policy: http://www.debian.org/doc/packaging-manuals/python-policy/