UDIB

UDIB is the Unattended Debian Installation Builder. It provides a handy commandline utility for creating preseeded Debian installation ISOs. Preseeded ISOs allow partially or fully automated Debian installations on bare metal (or anywhere else).

What's preseeding?

A preseed file is a text file which provides the Debian installer with previously set (preseeded) answers during the installation process. Preseeding a Debian ISO allows you to heavily reduce the amount of user interaction required during an installation, or even fully automate it. The preseed file is written by you and then injected into the installation image. When you start the installation, any answers you have provided to the debian installer as part of your preseed file are automatically applied during the installation. If you want to know more, you can have a look at Debian's official guide or at the Debian wiki's quick overview, both of which explain preseeding much better than I can.

How does UDIB work?

UDIB's main purpose is the injection of preseed files into existing Debian installation ISOs. In a nutshell, it does this by extracting the ISO, adding the preseed file to it, and repacking the ISO again. You could do all of this manually of course by following the basic and advanced guides for ISO repacking on the Debian wiki, but UDIB does all of this for you.

Dependencies

UDIB has some hard- and software requirements, both regarding the target machine for which it can build ISOs, as well as on the build machine on which UDIB is run.

Target Machine

Images built using UDIB can be used to install Debian on systems satisfying these requirements:

• CPU Architecture: x86 (64-Bit)
• Network: an ethernet connection with internet access

Build Machine

Using UDIB to create ISOs requires the following software:

• GNU/Linux
• python3 (3.10.4 known to work)
  • required python packages can be installed in a virtual environment
• xorriso (1.5.4 known to work)
  • Debian (bullseye): xorriso
  • Arch Linux: extra/libisoburn
• gpg (2.2.32 known to work)
• GNU cpio
  • preinstalled on most distributions

Internet access is (obviously) required if you want to fetch any files using UDIB.

Quick Start Guide

This short guide explains how to build a Debian ISO with a customized and automated installation:

1. make sure you have all the required software installed
2. clone this repo and cd into your local copy
3. (optional) create and activate a virtual environment: python3 -m venv .venv && . .venv/bin/activate
4. install the required python packages: pip install --user -r requirements.txt
5. get an example preseed file: ./udib.py -o my-preseed.cfg get preseed-file-basic
6. customize your installation by editing my-preseed.cfg (the comments are pretty self-explanatory)
7. create a Debian ISO with your preseed file: ./udib.py -o my-image.iso inject my-preseed.cfg
8. boot from your newly created ISO my-image.iso on your target machine (or in a VM)
9. in the Debian installer menu, navigate to Advanced options > Automated install
10. drink some coffee
11. return to your new Debian system

Depending on how many answers you provided in the preseed file, the installation may require some manual interaction. Preseed files are very powerful, and if you need more customization you can have a deeper look into how they work. You can also use UDIB to get the full preseed example file: ./udib.py get preseed-file-full and use that as a starting point.

Detailed usage guide

You can view help at the commandline using ./udib.py --help for general options and ./udib.py COMMAND --help for help with a specific subcommand.

The name and destination of files produced by udib.py can be specified with the --output-file option. Alternatively, you can use the --output-dir option to specify the directory where produced files will be saved, without having to name them explicitly (default names will be used).

Retrieving example preseed files or vanilla ISOs

As a starting point for creating your own preseeded ISO, you can retrieve one of Debian's example preseed files or an unmodified Debian ISO using UDIB:

udib.py [--output-file FILE | --output-dir DIR] get WHAT

WHAT must be a specific string and can be either one of:

• preseed-file-basic to download Debian's basic example preseed file (sufficient in most cases)
• preseed-file-full to download Debian's full example preseed file (has a LOT of customization options)
• iso to download the latest, unmodified Debian stable x86-64 netinst ISO

Creating a preseeded ISO

To inject an existing preseed file into an ISO, you can run the following command:

udib.py [--output-file FILE | --output-dir DIR] inject PRESEEDFILE [--image-file IMAGEFILE]

where PRESEEDFILE is the path to your preseed file. If you don't specify an --image-file, UDIB will download the latest Debian x86-64 netinst ISO and inject your PRESEEDFILE into it.