Debian Installer internals

Frans Pop

This document is free; you may redistribute it and/or modify it under the terms of version 2 of the GNU General Public License.


The Debian Installer is sometimes described as a mini Linux distribution which gives an indication of its complexity. This document gives an introduction to the inner workings of the installer when it is running, its components (udebs) and its build system.

Table of Contents

1. Introduction
2. Running Debian Installer
2.1. Installation methods
2.2. The boot process
2.3. The Debian Installer Menu
2.4. Hooks provide additional flexibility
2.5. Some special tools
2.6. Automating the install using preseeding
2.7. Debugging the installer
3. D-I components or udebs
3.1. Contents of a udeb
3.2. Creating a udeb
3.3. Library udebs
4. Building installer images
4.1. The D-I images
4.1.1. Debian Installer images
4.1.2. CD/DVD/BD images
4.2. Requirements for building
4.3. Build targets
4.4. The build system explained
4.4.1. config
4.4.2. pkg-lists
4.5. Result of the build
4.6. Library reduction
4.7. Using localudebs
5. Maintenance of the installer
5.1. Updating to a new Linux kernel version
5.2. Dropping a deprecated filesystem
A. Menu Item numbers
B. Available hooks
B.1. run-parts type hooks
B.1.1. System boot
B.1.2. General purpose run-parts hooks
B.1.3. Special purpose run-parts hooks
B.1.4. Partitioning — deprecated components
B.2. Other hooks
B.2.1. Hooks available for customization
B.2.2. Hooks reserved for internal use