I've been having great success with this one at my day job. Being able to apply all the container workflows to VM images has been a boon.

Or "something that nix already solve, but with documentation"

Most likely context I'm going to try it is in a systemd-nspawn context. Lightweight process namespace ("containers") closer to the native modern linux server runtime (systemd all the way).

one image to deploy mostly without additional tooling on any systemd-based OS (which mounts the image and integrates the units from it), on a VM (just use it), or on bare metal (probably needs to be built on a full image but still can just use it assuming that is the case).

It is used by the systemd team to test systemd on a bunch of distros.

https://github.com/systemd/systemd/blob/main/.github/workflo...

I use [pi-oven](https://github.com/keichi/pi-oven) for my raspberry images. Not perfect, but kind of works and removes a lot of hassle for the provisioning.

Could not quickly find out from the project page an example on how to bake rpi images with mkosi, but the descriptions do point towards somewhat similar use case :shrug:

I've checked on this several times over the years, and I think the answer will probably be no for a long time, or forever. The RPi boot process is a bit arcane and specific. Systemd's philosophy seems to want to target the 95% use case, but maybe the sheer size of the RPi sphere will provide enough pressure.