Definitely. That’s a great way to run different option together.
I was just using the DE as an example to demonstrate how cleanly NixOS can add and remove packages. The clean removal of packages with lots of configs is something that most distros struggle with.
No, I fully understand it. But if you build the whole system where every package is isolated, none of the packages interfere with each other, and every package is tested across a wide array of architectures, you can just as safely put together your ideal OS setup and don’t have to deal with being locked into very simple and bare system.
The right place for immutable OSes is if you’re using it as a server for container workloads, where you will never customize the base system. Or if you never want to customize your system. Yes, you can customize the system image, but it breaks all the guarantees that the images gives you because the packages themselves are not isolated and by bumping a wrong dependency for a custom packages you can still break the whole system.
Already has that. And if you use flakes, you can fully lock down your package versions that way the install is 100% identical on every machine no matter when you run it.
My favorite example of how idempotent NixOS is has to do with the DE. If you’ve ever looked at switching from gnome to KDE, or the other way around, most distros suggest to just re-install because each DE leaves so much cruft around and it’s so hard to remove everything in a safe manner.
With NixOS, you just change one line in your config, and the DE is cleanly swapped.
I would separate NixOS from other immutable distros. NixOS is really about giving you blank slate and letting you fully configure it.
You do that configuration using a static config language that is able to be far more idempotent than Andible. It’s also able to define packages that are well contained and don’t require dynamic linking setup by manually installing other packages.
Immutable distros, on the other hand, really have no advantage to your setup and will probably feel more restrictive. The main use I see for them is for someone new or lazy that wants to get a working system up and running quickly.
I would say it’s actually easier in many cases. Nix has really fantastic packaging tooling. You do have to learn a bit of the nix language, however (not become an expert).
The issue comes when trying to build from source. In most other distros, ou just follow the readme. In nix, you have to package it.
Your summary of the language is spot on. I still hope that more distros take inspiration from the declarative config and try to move in the direction, or nix supports a better language in the future. I think that ultimately that’s what the average linux user would want. The ability to still customize in a safe manner. Silverblue, and others, are and will remain a great option for the new or indifferent user.
On your point about the transient phase, nix actually does that by default already. It installs everything at a separate path and then flips over in one go. You can even pick the mode, either try to do a live switch as you describe, or on boot. I don’t know if I see many benefits to images there.
I am at a second place now that uses NixOS in a corporate setting, and it is much easier than maintaining the CoreOS images, or similar. I’ve had some many broken builds of CoreOS images because something goes wrong between the custom packages and the base CoreOS images, I would rather just run an Ansible script at this point. Also, you end up using the exact same test suite for NixOS images as for your other images, so the same guarantees end up being met.