Reproducible builds

This document isn't describing what reproducible builds are, or why we want them, there's plenty to be found elsewhere. The Debian Policy also has a section on it.

Expected differences between buildds and rebuilders

With the arrival of rebuilders of the Debian archive, the results of rebuilds will be used by the migration software to influence the migration of packages from unstable to testing. To be clear about difference with respect to the buildds that the Release Team expects to be present on rebuilders, the following list is intented to be canonical.

General system properties

• system time
• system uptime
• CPU model, load, number of cores
• RAM amount, speed
• kernel version, process scheduling, various kernel settings
• disk space, speed
• file order, mtime, ctime, atime, inodes
• /sys/* (due to different system)

Specific to debrebuild

• apt, openssl, ca-certificates not installed by default (these packages are not listed in the buildinfo file)
• fakeroot not used for Rules-Requires-Root (not listed in the buildinfo file)
• dpkg install order is not guaranteed
  • can have effects on maintainer scripts, UIDs added by packages..
• /etc/apt/sources.list* content
• /run/* (due to mmdebstrap cleaning it up)
• /var/log/*
• LD_LIBRARY_PATH does not contain fakeroot when running with Rules-Requires-Root: binary-targets

Specific to reproduce.debian.net

At the moment of writing, the Release Team is aiming to use at least reproduce.debian.net.

• tmpfs vs ext4
• nice level