Sounds interesting. Is rpm-ostree config declarative? Can it install multiple versions of packages and libs simultaneously? Are adding custom packages to your setup a matter of a few lines of additional config, or must you learn RPM? Can you manage home directory config as well?
There's the treefile [1] for declarative config, no need to learn RPM, just add package names and any extra config. As for managing home and multiple versions simultaneously, I think those are non-goals for this tool.
I meant creating an entirely new package from scratch.
Regarding non-goals - I think that exposes the fundamental difference. rpm-ostree isn't "better". It's trying to solve different problems. The use case you described is a very small part of what Nix makes possible. Nix isn't just trying to fix or improve on existing systems - it present a fundamentally new abstraction that can be used for many purposes. Yes, you can configure and snapshot a list of packages, but that's a tiny part of it. With Nix, the capability allows you to also create any environment from scratch, isolated from other environments on your machine, e.g. for CI or development, or running some obscure python repo.
Yes you're right, better wasn't a good choice of words. My comment was in the context of replacing Ansible with Nix for making a reproducible system, as per the linked article. I wanted to point out that alternative which will be much more familiar to most people, who perhaps aren't ready to jump to an entirely new paradigm, but still want a declarative config. But undoubtedly Nix is much more powerful. I myself have been meaning to try out Nix on top of my rpm-ostree system, for dev environments.
