zbm-regen-pacman-hook

Arch Linux pacman hook to automatically recreate ZFSBootMenu images after upgrades. This hook is intended to work with quico.space/quico-os-setup/arch-zbm, a root-on-ZFS installation script that uses ZFSBootMenu as its boot loader.

Setup

Not explicitly listed here as a step but still relevant: This pacman hook only makes sense if you're using ZFSBootMenu images and have the homonymous zfsbootmenu package installed.

Get started like so:

1. Clone repo into arbitrary path <repo>
2. Symlink to hook file, for example

   sudo ln -s <repo>/pacman-zbm-image-regen.hook /usr/share/libalpm/hooks/pacman-zbm-image-regen.hook
   

What's it do?

In pacman whenever the zfsbootmenu package or your kernel are getting updated this hook will regenerate the ZFSBootMenu image via generate-zbm which will in turn store a new file in its image path as configured in /etc/zfsbootmenu/config.yaml.

This happens as a PostTransaction in pacman.

Assumptions

Per headline this hook is intended to work with quico.space/quico-os-setup/arch-zbm. Before using this hook for any purpose other than an arch-zbm Arch Linux installation please closely review what it does and adapt to your use case as needed.

This hook is working on arch-zbm machines that use either UEFI or legacy BIOS.

The zfsbootmenu package and generate-zbm binary in particular don't care where newly generated images need to be stored. After an arch-zbm installation you're left with an /etc/zfsbootmenu/config.yaml file that instructs generate-zbm to store new image files in a sensible location.

UEFI vs. legacy BIOS

On a UEFI system new ZFSBootMenu images are named vmlinuz.EFI and vmlinuz-backup.EFI. EFI boot loader entries can and do remain static to always looks for these two exact EFI image file names.

On a legacy BIOS machine ZFSBootMenu creates split images: One vmlinuz-bootmenu(-backup) kernel and one initramfs-bootmenu(-backup).img initrd. Here, too, your /boot/syslinux/syslinux.cfg config file can and does remain static to always look for these exact file names.

Triggers

The hook triggers on several pacman events:

1. An upgrade of zfsbootmenu package
2. Upgrades or installation on files that match:

   Target = usr/lib/modules/*/vmlinuz
   Target = usr/lib/modules/*/extramodules/*
   

3. All pacman operations on files that match:

   Target = boot/*-ucode.img
   Target = usr/lib/booster/*
   Target = usr/lib/initcpio/*
   Target = usr/lib/initcpio/*/*
   Target = usr/lib/dracut/*
   Target = usr/lib/dracut/*/*
   Target = usr/lib/dracut/*/*/*
   Target = usr/lib/kernel/*
   Target = usr/lib/kernel/*/*
   Target = usr/src/*/dkms.conf
   

Development

Conventional commits

This project uses Conventional Commits for its commit messages.

Commit types

Commit types besides fix and feat are:

• build: Project structure, directory layout, build instructions for roll-out
• refactor: Keeping functionality while streamlining or otherwise improving function flow
• test: Working on test coverage
• docs: Documentation for project or components

Commit scopes

The following scopes are known for this project. A Conventional Commits commit message may optionally use one of the following scopes or none:

• script: Work related to commands triggered by pacman
• hook: Configuring the hook(s)
• meta: Affects the project's repo layout, readme content, file names etc.