Contents

  1. Introduction
  2. How does Ubuntu differ from Debian?
    1. Purpose and Scope
    2. Licensing
    3. Packages
    4. Package maintenance
    5. Bug tracking
    6. Relationship to Canonical
  3. What is MOTU?
  4. Why does Ubuntu need to change my packages? What kind of changes are made?
  5. What can I do if I feel that an Ubuntu developer or member is behaving inappropriately?
  6. How does Ubuntu cooperate with Debian?
    1. How can I obtain patches from Ubuntu?
    2. Why aren't *all* patches submitted to the Debian BTS?
    3. How can I minimize the Ubuntu delta for my packages?
    4. How can I ask Ubuntu to copy my package from Debian?
    5. Why does Ubuntu have an older/buggy version of my package?
    6. How can I indicate that a bug filed in Ubuntu against one of my packages is fixed in Debian?
    7. How can I get upload rights in Ubuntu for the packages I maintain in Debian?
    8. How can I work with the Ubuntu Security team?
  7. Resources
  8. Contact
  9. Todo
  10. Suggestions

Introduction

This document is intended to provide practical information about Ubuntu specifically for Debian developers.

How does Ubuntu differ from Debian?

Purpose and Scope

Ubuntu has a narrower focus than Debian in many ways. For example, Ubuntu supports only a subset of the architectures that Debian does, and targets specific users (for example, desktop and mobile users and server administrators), while Debian seeks to be more universal.

A good introduction page is about-ubuntu.

Licensing

Ubuntu has four components (like Debian's main, contrib and non-free), distinguished by licence policy and support terms. The following table summarizes the differences:

Source packages in Ubuntu components:

Free software

non-free software

Officially supported

main (~2000 packages)

restricted (~5 packages)

Unofficial

universe (thousands)

multiverse (hundreds)

Officially supported packages (main and restricted) receive security updates sponsored by Canonical, and more rigorous QA relative to the Ubuntu release cycle. The efforts of the Ubuntu core team are focused there.

The MOTU team cares for the packages in universe and multiverse (which are comprised mostly of packages from the Debian archive) on a best-effort basis, as there are a large number of packages relative to the resources of the team. Therefore, a vast majority of these packages are used unchanged from Debian, rebuilt in an Ubuntu build environment, and do not receive personal attention from an Ubuntu developer.

If a package depends upon a non-free package, it will be placed into multiverse. Multiverse is the union of contrib and non-free in Debian.

Packages

Most source packages in all Ubuntu components (about 4 in 5 at the time of this writing) are copied unmodified from Debian. There is also software in the archive which has been packaged by Ubuntu developers, and packages created specifically for Ubuntu. There are other external package sources available (e.g. Gooogle Chrome or Launchpad PPAs.)

In some cases, the same upstream software is packaged separately in Ubuntu and in Debian, though this is to be avoided unless there is a justifiable reason to do so.

Where packages in Debian and Ubuntu have a common heritage, the packages use version numbers which reflect this.

Package maintenance

Unlike Debian, Ubuntu packages usually do not have a designated maintainer. In effect, all packages in Ubuntu are maintained by teams, and there is no concept of an NMU. Packages in Ubuntu main and restricted are maintained by the Ubuntu Core Development Team, while packages in Ubuntu universe and multiverse are maintained by the Ubuntu Development Team. If you need to discuss a specific change, try poking the last person who changed the package (see the changelog at http://changelogs.ubuntu.com/).

Ubuntu does not permit binary uploads (builds performed by the developer on their own system) for any architecture. All builds are performed in clean chroots by Launchpad, and uploads are source-only (dpkg-buildpackage -S).

Bug tracking

Ubuntu tracks bugs in Launchpad. The Launchpad bug tracker makes it possible to keep track of bugs in multiple contexts, for example, if a bug is fixed upstream but not in Debian, or fixed in Debian but not in Ubuntu. It can also store links to bugs filed upstream and in Debian, and notify Ubuntu developers when their status changes. More information about bug tracking in Launchpad can be found at https://help.launchpad.net/BugTrackingHighlights and the documentation for the email interface is at https://help.launchpad.net/Bugs/EmailInterface.

Relationship to Canonical

Ubuntu, like Debian, is a free software project which is open to anyone to participate. However, it differs from Debian in that many key project resources, including servers, bandwidth and a number of core developers, are provided by Canonical. Canonical is a for-profit company which derives revenue primarily from services related to Ubuntu, such as support contracts.

What is MOTU?

With the creation of the universe component, volunteers were needed to look after these packages. A team called The Masters of the Universe (MOTU) was formed for this purpose. MOTUs sync (import without modification) or merge (import with Ubuntu-specific changes) packages from Debian. MOTUs also sometimes construct Debian-format source packages for use in Ubuntu universe directly from upstream sources. MOTUs handle bugs reported on software inside universe and multiverse.

The process to join the MOTU team is explained over here. As a Debian developer you won't have much trouble with the technical side of packaging, so the process will be a bit quicker. When applying for becoming a MOTU, two criteria are evaluated: technical skills and teamplay + knowledge of Ubuntu processes.

Why does Ubuntu need to change my packages? What kind of changes are made?

There are many reasons why packages in Ubuntu diverge from Debian, including:

What can I do if I feel that an Ubuntu developer or member is behaving inappropriately?

Technical issues should be raised with the Ubuntu Technical Board. Non-technical issues should be raised with the Ubuntu Community Council. Information about both bodies may be found on the governance page.

How does Ubuntu cooperate with Debian?

For many packages in main, Ubuntu has good working relationships with the Debian maintainer(s) and is involved with the core Debian development. Many volunteer developers are active in both Debian and Ubuntu camps.

Some resources can be found at the end of this page.

How can I obtain patches from Ubuntu?

Why aren't *all* patches submitted to the Debian BTS?

How can I minimize the Ubuntu delta for my packages?

How can I ask Ubuntu to copy my package from Debian?

This is called syncing, and is outlined in the document SyncRequestProcess. The easiest way to do this is to install the ubuntu-dev-tools package, and use the requestsync script from there. This script requires a Launchpad account. See requestsync(1) for detailed usage information.

Why does Ubuntu have an older/buggy version of my package?

Because Ubuntu has a different release cycle than Debian, freezes occur at different times. Near the beginning of an Ubuntu release cycle, packages from Debian unstable are automatically copied to Ubuntu on a regular basis, but later, this is only done if the package is explicitly copied by an Ubuntu developer after being reviewed for compliance with the current freeze guidelines. Under some circumstances, the approval of a third party is required.

An outline of a normal Ubuntu release schedule can be found on ReleaseScheduleTemplate.

How can I indicate that a bug filed in Ubuntu against one of my packages is fixed in Debian?

Similar to what dak does for Debian, Launchpad looks at the .changes files for sourceful uploads for a Launchpad-Bugs-Fixed field, containing a list of bugs that should be marked as closed. This field is populated from the changelog by looking for strings of the format LP: #<bug number>.

Since each package synced or merged to Ubuntu from Debian will have a .changes file that references the Debian changelog, if you include an LP: line in your changelog when uploading to Debian, the Ubuntu bug report will automatically be closed when that package version is included in Ubuntu.

How can I get upload rights in Ubuntu for the packages I maintain in Debian?

Per-Package Uploaders are developers with a special interest in a specific set of packages in Ubuntu. They are granted direct upload permissions to the Ubuntu archive for that set of packages. If you are mostly just interested in the packages that you maintain in Debian, this may be the path for you. There is a slightly streamlined procedure for Debian Developers wishing to have upload rights for their packages. See the application process page for more details.

How can I work with the Ubuntu Security team?

Please see SecurityTeam/ForDebianDevelopers for more information.

Resources

Work in progress (please help) :

Contact

If you have questions about the material on this page, or have an issue regarding collaboration between Debian and Ubuntu, please contact debian@ubuntu.com.

Todo

Content which should be added to this page:

Suggestions

Ideas which require further discussion or development:

Ubuntu benefits from a strong Debian, and Debian benefits from a strong Ubuntu. - MarkShuttleworth

Every Debian developer is also an Ubuntu developer, because one way to contribute to Ubuntu is to contribute to Debian. - MarkShuttleworth

We incorporate Debian changes regularly, because that introduces the latest work, the latest upstream code, and the newest packaging efforts from a huge and competent open source community. Without Debian, Ubuntu would not be possible. - MarkShuttleworth

Go back to Debian.
CategoryDebian

Ubuntu/ForDebianDevelopers (last edited 2017-11-27 16:03:13 by bryanquigley)