First Steps with NixOS

Introduction

For the longest time, when using Linux distributions, I chose those that were Debian-based. I still do for servers. However, on the dekstop I switched to Manjaro, which is Arch-based, about two years ago. Two years is a long time without distro-hopping, so I was long overdue. I've been following the NixOS project for some time but since I was happy with my setup, I didn't consider making the switch. However, a month ago, I decided to dip my toes. I installed NixOS on a flash drive and started tinkering with it. In this post, I'll provide some of my initial impressions and things I find appealing about the OS.

Declarative configuration

One of the first things I did when I booted into my new NixOS installation was get familiar with the configuration file. The configuration file is authored using the Nix programming language and it's the place where you configure your entire system, including services, packages, and desktop environments. The best way I can describe it is a Dockerfile for your desktop. If interested, you can find my config file on the scripts section of this website.

There's a few advantages to this approach:

  1. Configurations are stored in a single place - The advantage to this is, I don't have to figure out where the configuration files for each of the components of my system are. I can manage everything in one place. A perfect example where the configuration file goes beyond what I expected was being able to include my bash configuration. Typically, I'd have that configuration in my bashrc file. With NixOS, I can just include that in the configuration file as follows:

    programs.bash = {
    shellAliases = {
        emacs="emacs -nw";
    };
};

  2. Enables composition - Because the configuration file is effectively a script, I can modularize the difference pieces. For example, if I wanted to split out my service and package configurations into separate files, I can do so and reference those individual files from my configuration file, separating concerns while still keeping my system configuration simple.

  3. Version control - Because the configuration file is just like any other plain text file, it means I can check it into the version control system or cloud service of my choice and manage it that way. In doing so, not only can I roll back using the built-in NixOS mechanisms, but I have another layer of security in case I need to recover that file.

Now, because I can define everything about my system in the configuration file, this means I can seamlessly rebuild my entire system using this single file in a reproducible manner.

Reproducible builds

I got to experience first-hand how the configuration file can simplify out-of-box-experiences and system configurations. Initially, I did not install NixOS on my main hard drive. All of my configuration and learning took place on a flash drive. Once I got my configuration to a place I was satisfied, it was time to take the plunge and reimage my PC. In the past, when I've done something similar, I've had to document everything I did when configuring my system. That's where posts like Setting up a new Ubuntu PC come from. With NixOS, all I needed to do was replace my configuration file with the one I configured on the flash drive. Then, when I ran nixos-rebuild switch, my system was configured exactly like the one on the flash drive.

Risk-free software evaluations

This is something I haven't tried yet, but I could easily see it coming in handy. Sometimes I might need a piece of software to do one thing or maybe I want to see whether it'll solve a problem I'm facing. In order to try it out and use it, I need to install it globally. This can cause changes to my system permanently that I don't want. With NixOS, you can create ad-hoc shell environments. These environments make temporary changes to your system, so you can evaluate a piece of software or use it that one time. Then, when you exit the environment, the software is no longer installed in your system.

Large package selection

A large package selection to choose from is something I got used to with Manjaro. Being an Arch-based distribution, I had access to the Arch User Repository (AUR). Moving to NixOS, it's nice to know that in this area, NixOS offers great support. Additionally, NixOS has built-in support for Flatpak

Still exploring

There's still a few things I don't really get. For example, when installing the .NET SDK, I wanted to have side-by-side installs of the latest STS (7.0) and LTS (6.0). However, including the package names in my configuration file didn't work as expected. Instead I had to use the following convention.

(with dotnetCorePackages; combinePackages [
    dotnet-sdk
    dotnet-sdk_7
])

As I learn more, this will probably make more sense but for now it's a mystery.

Conclusion

Overall, I'm happy with NixOS and I can see myself using it for the long-term. Hopefully longer than two years. I'm not a gamer so I can't say how well it does in that front. For web browsing and software development though, I really like what NixOS has to offer. If some of the things I mentioned above sound interesting, I'd encourage you to install it on a flash drive and start tinkering with it.

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