| I think most people who use Nix on Redhat, Debian, Ubuntu and so on probably don't use it to provide system services like `sshd`. A more common use would be to install a package in a version that isn't available, or where you would need to link to a different version of the library than is available on your system. Nix makes the dreaded autotools dance much more bearable, even for someone like me who doesn't really know any C++. Another common situation is when you are a software developer working on many projects with overlapping but slightly different dependencies where slightly different sometimes turns out to be incompatible. Ideally you could handle this with `virtualenv` or your language's equivalent, but I often find I end up with multi-language projects where this just doesn't work. For example, if one of my Python libraries also wants some C libraries in a particular version. Nix is ideal for such a situation. Docker and docker-compose can work too, but, eh, it's kind of slow, and it'll probably break a few months down the line when all the JavaScript library authors decide that building things with `plink` is gauche and everyone should move to `smooch` instead, or when CRAN decides it doesn't want to keep these old versions of libraries any more. And, what do you do about your linting and formatting and code completion tools? Do those go inside Docker too, because then the Docker slowness really shows up. (If you don't have these sorts of problems often, then Nix may not help you all that much. I guess reducing the amount of stuff you install and uninstall with `apt` or `rpm` probably still reduces the rate at which your system rots though.) Having said all that, if you decided that you did want to use Nix to provide packages for your system services, then there's no difficulty in specifying a mutable config file in /etc/wherever. That part would be handled in your init system config (say, a systemd unit) instead of inside Nix. It's for NixOS that you would use the Nix language to configure everything, and I've found that experience to vary quite a lot. I've used some obscure or packages which didn't expose enough of the configuration to do what I needed by default, and so I had to make my own version. This can be pretty annoying and time consuming. Nixpkgs' maintainers get a lot of work done individually because of the tooling, but there just aren't enough of them yet. On the other hand, I've found that configuring popular things like Nginx and Postgres is often much easier in the Nix language. It's much harder to make a small syntax error, you have access to some helpful templating constructs, and you can re-use the same constants for different config files in different packages. Similarly, for NixOS, configuring your systemd services is really well handled. Wow, that ended up long winded. Sorry. |