Test Debian Build

[JohnMertz]

One of the UBlue contributors is working on a Debian image builder.

It doesn't actually seem overly complicated to add Bootc support to Debian (just requiring a manual installation with Cargo).

It would be incredible if we could maintain a Debian base. There is uncertainty with RedHat's influence over CentOS as to whether it could be discontinued, significantly changed, or locked behind a paywall in the future.

A few major considerations:

• The projects mentioned builds from unstable (Sid).
• The images being built include the Rust toolchain in the final image.
• The simple static Containerfile in the example loses some of the niceties of Cayo's C Preprocessor and multiple build targets.

I'm going to briefly make a 'debian' branch and see what it takes to get a very basic server image built (with packages) using Trixie and while leaving as much of the Justfile and Containerfile.in intact as possible.

[JohnMertz]

Trixie does not have an up-to-date version of libostree (version 2025-2 < 2025-3). So it is necessary to use Forky (Debian 14/Testing).

The container size after compiling bootc is huge (>6GB). Most of this is the Rust build dependencies. It should be possible to build this in a multi-stage Containerfile where the necessary files get extracted from the bootc builder container after mounting to the SpamTagger container.

However, the files that get transferred out are going to have dependencies on the Forky version of packages meaning that we'd need to use Forky for SpamTagger as well. I'm not entirely opposed to this. The bootc/ostree model is pretty secure, so potentially vulnerable new packages don't pose a big risk. The biggest problem I've had with using Testing in the past is that some packages simply don't get packaged for Testing immediately after the new Stable is released. I think we can probably proceed with this as long as all of the major dependencies exist.

[JohnMertz]

An alternate organization, frostyard has sprung up and is doing a lot of tremendous work, very quickly, to build Debian Stable OS images with BootC.

I now have the frostyard branch which is re-based to build directly off of frostyard/debian-bootc-core which eliminates the need to build bootc/ostree/composefs on my own!

This is looking very promising! In the worst case scenario, I will just need to replicate a lot of the work that they are currently doing in this repo, but in the best case, I can now strictly focus on configuring SpamTagger Plus on top of the base image. Given that debian-bootc-core is essentially the bare minimum packages layered on top of docker.io/library/debian:stable to make it Bootc compatible, the steps to make a Bootc image on top of it should be nearly identical to installing on top of a generic Debian appliance (except with extra caution around writable directories). This is to say that it should be possible to create a single install script which works for Bootc and the same script should then work for a mutable Debian also.

I'm almost certain that this is the right way forward and will just wait until #12 is merged before closing this.