Installing NixOS

This is just a small introduction to a Linux distribution that’s been getting traction lately, especially in functional programming ecosystems.

NixOS: The purely functional Linux distribution

NixOS is a really cool idea: the OS and its various components and apps is fully determined by its configuration, in a deterministic fashion. In other words, with NixOS systems become stateless and immutable. Nix is also the language that is used to express this configuration: it is a pure functional and lazy DSL, designed for system configuration. Being a functional and declarative language, it allows building abstractions for configuration and composable bricks that can be assembled to produce a certain environment.

/etc/nixos/configuration.nix

The entire system is determined by means of the configuration.nix file. This is the root file for the configuration. Nix has an import mechanism, so configurations can be organized in multiple files and folders like real software projects. Here a example of a very simple configuration.nix file which defines a minimal system:

{ config, lib, pkgs, ... }:
{
  boot.loader.grub.device = "/dev/sda";
  fileSystems."/".device = "/dev/sda1";

  networking.firewall = {
    enable = true;
    allowedTCPPorts = [ 80 ];
  };

  environment.systemPackages = with pkgs; [
    wget
    git
  ];

  services = {
    sshd.enable = true;
  };
}

The { arg1, arg2, ..} : {} notation is how you define functions in the Nix language. Note how the system configuration itself is just a function!

Installation

The installation steps I went through are documented in this github repo. This repository is also where I store all my personal nix configuration files to restore machines or grab elements of configuration.

Reproducibility

In a nutshell, with NixOS installing a fully-configured system boils down to:

  1. bootstrapping it with the nixos livecd or usb key
  2. downloading (or editing) the configuration
  3. running the nixos-install command

Improvements and changes to system configuration can be tracked with version control, and easily propagated to all the machines via nixos-rebuild.

With NixOS, it’s never been easier to find oneself at home in any environment!

Links

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.