..
   SPDX-FileCopyrightText: 2024 Matteo Settenvini <matteo.settenvini@montecristosoftware.eu>
   SPDX-License-Identifier: CC-BY-SA-4.0

.. post:: 9 Aug, 2024
   :tags: linux, boot, debian, debug
   :category: tech
   :author: Matteo Settenvini
   :location: Berlin, DE

####################################
Debugging Distribution Boot Problems
####################################

I use Debian, but this method can easily be adapted to other distributions.

In a couple of decades or so running Debian Unstable (and occasionally, Testing), I realized that the most time-consuming bugs to analyze are due to packages breaking during boot time.

This includes:

* bootloaders,
* initramfs problems,
* init system.

With the goal of quickly submit an upstream report, I need to tell if the issue is due to my machine's unique setup, or if it is reproducible on a vanilla install. I have thus found a quick method for testing: creating a VM and saving boot logs via serial console to files.

The steps are roughly:

- install Vagrant and Ansible (``apt install vagrant vagrant-libvirt ansible``).
- create an empty folder, for instance ``~/Projects/boot-problems``.
- create a ``logs`` folder inside. Here the boot logs will be dumped.
- create the following files in the topmost folder:

  .. literalinclude:: /files/debian-vagrant/requirements.yml
    :language: yaml
    :caption: requirements.yaml

  .. literalinclude:: /files/debian-vagrant/Vagrantfile
    :language: ruby
    :caption: Vagrantfile

  .. literalinclude:: /files/debian-vagrant/playbook.yml
    :language: yaml
    :caption: playbook.yml

Now it's time to bring up the VM with ``vagrant up``. Once rebooted, ``vagrant ssh`` will give you a console.

Once it is running, you can easily trigger the update you think broke your system and get full logs of it as dumped under ``logs``.

This is invaluable if you need to attach something reliable to Debian's ``reportbug``.