NixOS made me go back to Windows

Declarative configuration

Without a doubt this is the feature of NixOS that I liked the most. Nix is, besides a package manager, a pure, functional, lazy, declarative and reproducible programming language to express (in .nix files) the state of your system. In other words, you will not have to execute commands that you will later forget nor will you have to modify files scattered around the system. You will perform all the configuration of your system through files that you can save in Git or wherever you want.

In these files you can specify the packages that must be installed, the hardware configuration (kernel, partitions, encryption, ...), the system users, the Google Chrome extensions that will be installed automatically, the GTK theme... practically everything. Altering the system configuration will be as simple as modifying these files and changing the system to the new state. Furthermore, you will be able to modularize the configuration as you like thanks to the import function. Wonderful.

{ pkgs, lib, ... }:

{
  # Firefox configuration: profiles, extensions, etc...
  programs.firefox = {
    enable = true;
    package = pkgs.firefox-devedition;
    profiles.felixsanz = {
      extensions = with inputs.firefox-addons.packages.${pkgs.system}; [
        ublock-origin
        decentraleyes
      ];
      settings = {
        "browser.tabs.warnOnClose" = true;
        "extensions.pocket.enabled" = false;
        "media.ffmpeg.vaapi.enabled" = true;
        # ...
      };
      userChrome = builtins.readFile ./userChrome.css;
      userContent = builtins.readFile ./userContent.css;
    };
  };

  # Environment variables associated with Firefox
  home.sessionVariables = {
    MOZ_DISABLE_RDD_SANDBOX = 1;
    MOZ_ENABLE_WAYLAND = 1;
  };

  # Set Firefox as the default browser
  xdg.mimeApps.defaultApplications = lib.genAttrs [
    "text/html"
    "text/xml"
    "application/xml"
    "x-scheme-handler/http"
    "x-scheme-handler/https"
    "x-scheme-handler/about"
    "x-scheme-handler/unknown"
  ] (_: "firefox.desktop");
}

Cool, isn't it? Keep reading, all that glitters is not gold.

Nix shell

The Nix shell is a powerful tool that allows you to temporarily modify the state of the machine. For example, you will be able to run an application without having it installed. You create a shell with that package/configuration and when you close it, it will leave no trace.

You could not have Python or Node.js installed globally, but when you go to work on a specific project, you open a shell with what you need and start working. This configuration can be stored in a shell.nix file like the following:

{ pkgs ? import <nixpkgs> {}}:

# The shell will be able to use Python 3.10 and the flask, requests and yeelight libraries

pkgs.mkShell {
  packages = with pkgs; [
    python310Full
    python310Packages.flask
    python310Packages.requests
    python310Packages.yeelight
  ];
}

The usefulness increases when combined with nix-direnv, an application that will automatically instantiate the shell.nix file when we enter the project directory via cd. It will make sure that everything is available.

The community

Perhaps the most valuable part of NixOS is not the technical part, but the human one. In support channels like their Discord community or the forum you will find friendly people always willing to help, with a patience that I have rarely seen. From the first moment I felt part of the community and at all times I received help when I needed it.

Unlearning everything you know

Do you have Linux experience? Well, congratulations, but it's not going to be of much use to you. Creating users with useradd, encrypting partitions with cryptsetup, configuring disks in /etc/fstab, creating shell aliases, configuring systemd services... nothing is going to help you. Ideally, you will perform all system configuration declaratively. This, as I said, is what I liked most about NixOS but relearning everything all over again is a slow and paintful process. It is what it is.

Home Manager

NixOS manages system configuration but not user-related configuration. Home Manager, a project created by third parties, takes care of that. It fills a gap that should not exist. Although overall it works well and is a great solution, it has some flaws that add more frustration to system setup. The advice I used to get the most was the less I use it, the better.

Options inconsistency

In NixOS a lot of configuration is done using options, for example:

{
  programs.zsh = {
    enable = true;
    dotDir = ".config/zsh";
    history = {
      path = "${config.xdg.dataHome}/zsh/history";
      extended = true;
      share = false;
      ignoreAllDups = true;
    };
    initExtra = "setopt INC_APPEND_HISTORY_TIME";
    syntaxHighlighting.enable = true; # <----- X.enable and enableX, ¿why?
    enableAutosuggestions = true;     # <----/
    shellAliases = import ./aliases.nix { inherit config; };
  };
}

The problem is that sometimes you need options that do not exist and you have to resort to manual configuration using xdg.configFile and derivatives.

On other occasions you will find options from the same package in both NixOS and Home Manager. Sway is installed via programs.sway.enable or wayland.windowManager.sway.enable? For a beginner all this is a wall. Another example, there are options for Google Chrome but not for Brave.

Not to mention all the time you spend generating this configuration, looking for the options, dealing with their inconsistencies, etc.

The options thing is all well and good but I found it to be quite chaotic and unreliable.

Awful documentation

The documentation is somewhere between awful and non-existent. Sorry, a poorly documented project loses a lot of value.

The wiki is abandoned and everybody recommends you not to use it. There is no documentation, you have to read the source code of the packages constantly. There are also no practical guides on how to do this or that. Also, the resources you find online (like blogs) are often outdated.

In short, it's exasperating. Thank goodness the community is very active and puts a lot of effort into helping others, but there comes a point that you feel bad for asking so many questions and sometimes you get stuck and you have no immediate help, and no way to find the solution on your own.

Just one version, really?

In Arch Linux you could install any old version of a package easily. Do you need CUDA 11.7, 11.8 or 12.1? No problem. On NixOS forget it, even if you make your own package you will need to manage all the dependencies by hand. There are only a couple of packages that are versioned (like python310 / python311), the rest... nothing. If you want an older or newer version of what nixpkgs offers, you're doomed. And if the package doesn't exist, good luck creating it. In other distributions you might be able to get by somehow, not here.

Nix shells for Python development

This has pissed me off, I'm not going to deny it. I don't even want to count the amount of hours I've wasted trying to get Python applications to work on NixOS. If you try to use venv and pip to install your project dependencies, you will start having a lot of problems with system dynamic libraries. No matter how hard you try, there is no way.

As we saw in the example above, many Python packages are found in nixpkgs:

{ pkgs ? import <nixpkgs> {}}:

pkgs.mkShell {
  packages = with pkgs; [
    python310Full
    python310Packages.flask
    python310Packages.requests
    python310Packages.yeelight
  ];
}

Both flask, requests and yeelight are available. Actually most of them are. But what do you do when the one you need is not available? Nothing. Waste days trying to get your application working. You can request the package in the GitHub repository to have someone take care of it, or try to collaborate by maintaining it yourself, but it's a very complicated task.

In this blog I'm sharing the experience I gain around Artificial Intelligence libraries, but NixOS has put so many obstacles in my way that I couldn't even do my thing. I've been waiting several months for them to publish onnxruntime-gpu, but there's no way, it's still there. It seems so complicated that nobody knows how to do it.

Besides, we're back to the same thing... just one version, really? In Python it is quite normal to install specific versions of dependencies, for example gradio==3.41.2. You can't do this on NixOS, it's ridiculous!

There was a time when I managed to get such an application working in exchange for losing 3 whole days trying. It's worth noting that these packages have to be compiled on your machine, so certain libraries took around 4 hours and needed more than 32GB of RAM, so I had to resort to swap as I didn't have enough memory. Beautiful experience, isn't it?

As if that weren't enough, weeks later when I upgraded the libraries, it broke again and I was no longer able to fix it no matter how many hours I put into it. That's when I started downloading the Windows 11 ISO.

pkgs = import <nixpkgs> {};
pkgs = import (builtins.fetchTarball {
  url = "https://github.com/nixos/nixpkgs/archive/2c7f3c0.tar.gz";
  sha256 = "1yswzpqq384ia4k2lyi8qicp07bvk5lsdx2y7wsd3sdvj79g72za";
})

In short, if you need this workflow stay away from NixOS.

NixOS is Linux

Right now I'm at a point in my life where I want to focus on what's important and don't want to waste time dealing with the operating system. And NixOS, it's still Linux. Every "weird" thing you want to do is going to take time and fights. From pairing a bluetooth headset to formatting a hard drive. And if on top of that in NixOS it is done differently... be prepared to spend time on it. Nothing new, I've been dealing with Linux for 20 years and I know what it's like.