Debian
Past, Present and Future

• • Steve McIntyre <93sam@debian.org>

• • Assistant Project Leader

• • 24th March 2007

Agenda 

• What is Debian? 

• Project structure 

• Process 

• Inside a Debian package 

• Derivatives – using Debian as a base 

• The future? 

• Getting involved 

What is Debian? 

• 3 aspects, interlinked: 

• • A Project 

• • An Operating System 

• • A Community 

Debian – the Project 

• Over 1,000 volunteer developers spread all over the world 

• • Large numbers in North America & Europe 

• • Smaller numbers in Australia & Japan 

• • Growing Latin American development community 

Debian – the Project (2) 

http://www.debian.org/devel/developers.loc 

Debian – the OS 

• Completely Free Software

• • Debian Free Software Guidelines 

• Support for 12 different architectures 

• • alpha, amd64, arm, hppa, i386, ia64, m68k, mips, mipsel, powerpc, s390, sparc 

• Largest GNU/Linux distribution 

• • Over 15,000 binary packages in last release 

• • Over 17,000 binary packages expected in the next release 

Debian – the Community 

• Open development 

• • We don't hide problems 

• Large amounts of communication 

• • Mailing lists, web sites and IRC channels 

• Large number of active users 

• • Users help each other, contribute packages, become developers 

How is Debian different? 

• Volunteer-driven 

• • No company in charge 

• Free Software 

• • Social Contract 

• • Debian Free Software Guidelines 

• Size 

• Packaging system 

• Stability & Support 

Social Contract 

• We declare that: 

• • Debian will remain 100% free 

• • We will give back to the free software community 

• • We will not hide problems 

• • Our priorities are our users and free software 

• • Works that do not meet our free software standards 

DFSG 

• Guidelines only – not hard rules

• Used to help decide what we will distribute in the Debian system

• main, contrib & non-free

DFSG (2) 

• Free Redistribution 

• Source Code 

• Derived Works 

• Integrity of The Author's Source Code 

• No Discrimination Against Persons or Groups 

DFSG (3) 

• No Discrimination against Fields of Endeavour 

• Distribution of License 

• License Must Not Be Specific To Debian 

• License Must Not Contaminate Other Software 

• Example Licenses 

• • BSD, GPL 

History 

• Founded in 1993 by Ian Murdock 

• Named after DEBra and IAN Murdock 

• The first major distribution developed “openly in the spirit of Linux and GNU” 

• Early work sponsored by the GNU project 

Leaders 

• Ian Murdock (1993 – 1996) 

• Bruce Perens (1996 – 1997) 

• Ian Jackson (1997 – 1998) 

• Wichert Akkerman (1999 – 2001) 

• Ben Collins (2001 – 2002) 

Leaders (2) 

• Bdale Garbee (2002 – 2003) 

• Martin Michlmayr (2003 - 2005) 

• Branden Robinson (2005 - 2006) 

• Anthony Towns (2006 – present) 

Releases 

• 1993: early development snapshots 

• 1994: v0.91 

• March 1995: v0.93R5 

• November 1995: v0.93R6 

• December 1995: v1.0

• June 1996: v1.1 (Buzz) 

• December 1996: v1.2 (Rex) 

Releases (2) 

• June 1997: v1.3 (Bo) 

• July 1998: v2.0 (Hamm) 

• March 1999: v2.1 (Slink) 

• August 2000: v2.2 (Potato) 

• July 2002: v3.0 (Woody) 

• June 2005: v3.1 (Sarge) 

• December 2006: v4.0 (Etch) ??? 

Project structure 

• Started with limited structure 

• Volunteers 

• Minimal “people management” 

• Package maintainers control their own work 

Various teams 

• Teams grow as jobs get bigger 

• Examples: 

• • ftpmaster 

• • debian-installer 

• • debian-cd 

• • release team 

Project decisions 

• DPL elected each year 

• • Delegates key project positions 

• General resolutions (GRs) 

• • Votes on important issues 

• Technical committee 

• Software in the Public Interest (SPI) 

Process: from Chaos... 

• Over a thousand Debian developers 

• Several thousand packages 

• Many thousand bugs 

• Millions of users 

... to Stability 

• Debian policy 

• Quality checking of packages 

• Testing (^2) 

• Release team coordination 

Policy 

• Comprehensive list of requirements for packages: 

• • What goes in a package, and where 

• • How to start & stop daemons 

• • Interactions with other packages 

• • Configuration files 

• • Upgrades 

• • etc. 

Quality checking 

• Lintian, linda 

• • Run by maintainer to check for packaging mistakes after packages are built 

• • Simple frameworks; new tests are added easily 

• piuparts 

• • Tests how well packages will upgrade from one version/release to the next 

Testing - Packages 

• Developers run their own tests before upload 

• Build-time test harnesses 

• Other developers and users report bugs 

• Bugs (hopefully!) are fixed, new uploads made 

Testing - Distribution 

• Uploads go to “unstable” distribution 

• After a period of time with no major bugs reported, packages become valid to migrate into “testing” 

• Archive maintenance scripts check for dependencies 

• Testing should be (almost) ready to release as “stable” at any point 

Release managers 

• Constantly monitor the state of the testing distribution 

• Co-ordinate uploads with package maintainers to make transitions smooth 

• Track large groups of packages as they work through the system (e.g. KDE, Gnome) 

• Responsible for deciding release goals and release dates 

Security team 

• Work with maintainers where possible 

• Security updates for “oldstable” 

• Security updates for stable 

• Security updates for testing 

• Coordination with other distributions 

• security.debian.org, DSAs 

Stable point releases 

• Organised by the stable release team 

• Made every few months 

• Collect together: 

• • Current security updates 

• • Highly-tested package updates to fix other serious bugs

• Update the archive 

• • rebuild CDs, DVDs etc. 

Collaboration 

• Many different source code control systems in use; choice of which is made by the developers 

• • cvs, subversion, arch, bzr, darcs, others... 

• Discussions via mailing lists 

• IRC for realtime discussion 

• Real-life meetings becoming more common 

• • Debconf, Extremadura 

Alioth 

• Sourceforge-like system 

• • cvs, svn, mailing lists, web space, ... 

• Used for collaborating on Debian work 

• • Projects like debian-installer, debian-cd 

• • Packaging work 

• Also hosts a number of non-Debian projects 

Inside a Package - sources 

• Packages are built from source by their maintainers 

• • Make changes, compile, test, sign, upload 

• Source packages are made up of: 

• • .tar.gz of source 

• • .diff. gz containing Debian changes 

• • .dsc file listing the details of these 

• One source package may make many binary packages 

Inside a Package - debian/ 

• debian/ subdirectory contains all the packaging metadata (similar to .spec): 

• • debian/copyright 

• • debian/control 

• • debian/rules 

• • debian/changelog 

Building packages 

• dpkg-buildpackage 

• • fakeroot 

• • sudo 

• Auto-builders 

• • sbuild 

• • pbuilder 

• Buildd 

• .changes file 

Binary packages 

• Architecture-specific or arch-all 

• Come as a.deb file; it contains: 

• • debian-binary (version info) 

• • control.tar.gz (metadata) 

• • data.tar.gz (package contents) 

• • Potentially other components 

• Layout conforms to policy & FHS 

Packaging system 

• Modular design 

• Simple low-level tool

• • dpkg installs and removes packages

• More intelligent higher level management

• • apt, aptitude, synaptic, etc.

• Packages.gz, Sources.gz, Release

• • Easy to create and mirror

Trust 

• Developers sign packages before upload 

• • Checked against keyring 

• md5 hashes stored in Packages.gz and Sources.gz 

• Release file signed 

• • Links together individual files, signed by the master archive key 

Derivatives 

• Not just a distro, can be a base 

• LOTS of derived distributions: 

• • Ubuntu 

• • Linspire 

• • Xandros 

• • Skolelinux 

• • Debian-jr 

• • many more 

Derivatives (2) 

• Why? 

• • Licensing 

• • Solid, stable base system 

• • Reduce effort 

• How? 

• • Take existing packages and add extras 

• • Rebuild packages where desired 

• No problem – everybody wins! 

The future – coming soon 

• Etch due next weekend! 

• • The system is hard frozen – RC bugfixes only 

• • Release and documentation teams working hard 

• • amd64 support added, m68k dropped 

• • Party! :-) 

Later this year 

• Debconf 7 in Edinburgh, June 2007 

• • Major conference 

• • Lots of work 

• • Lots of FUN! :-) 

Further on... 

• lenny after another 18 months? 

• Even more developers 

• Even more packages 

Getting involved 

• Test, report (and ideally fix!) bugs 

• Translation 

• Documentation 

• Help with packages 

• Sponsoring 

• New Maintainer Process 

Want to know more? 

• www.debian.org 

• mailing lists 

• IRC 

• ask me! 

• • Slides © 2007 Steve McIntyre <93sam@debian.org>

• • Released under GPL v2 at http://www.einval.com/~steve/talks/GLLUG-2007/