I’ve looked at a lot of other immutable distros and I might just end up using one of those, but I feel like taking on a bit of a challenge and there’s a few things I’m not very keen on with existing solutions (last paragraph is my idea if you want to skip the context).
Most immutable systems I’ve seen require a reboot in order to apply system changes. What is this, Windows? Yeah, reboots are quick but restoring my windows and getting back into my groove is not quick. Also, every immutable OS I’ve seen wants you to opt-in to a rollback. Rarely do I see the full effects of installing a package or altering a config immediately. By the time I notice an issue maybe it’s too late to rollback to before the change or maybe I’ve done a few other things since and I don’t want to rollback everything. I would much prefer to make “rolling forward” or persisting changes to be a very conscious process.
I started messing with BTRFS and I think I’ve come up with a process that will get me what I want, no matter the distro. Please poke holes in my idea. So I think I can use BTRFS to hold data for the rootfs in three different subvolumes (at minimum): root-A, root-B, root-Z. root-Z is my golden image and it represents what I want root to look like after reboot. root-A and root-B are the active and passive instances of rootfs, but which one is active will flip-flop after every reboot. So if I boot with A, B gets replaced with the contents of Z. In the meantime I can do whatever I want with A. Not sure how I’ll update Z (chroot or “promote” the active subvol to be Z) but without an update every reboot is an automatic rollback.
Thoughts?
I’m not planning to alter the system daily so, admittedly, this is a bespoke, non-trivial process to handle an uncommon use case. In general I haven’t run into the kind of issues that immutable distros proport to fix. I would say this is moreso an OCD friendly approach to OS management. I’m also hoping this setup will basically force me into using Ansible more and manual tweaks less.
I feel Guix and NixOS are a bit more in a league of their own due to their declarative nature. I’m on the fence if I want to go that far. Again, I’ll admit my knowledge of these systems is based on docs and I’ll probably have much different thoughts getting hands on.
And my goal is to rely on Flatpak and containers but if that was the answer then all the immutable distros out there are about as overbaked as my idea.