I wanted to switch to NixOS not only for its immutable kernel but for its declarative configuration. This allows to backup these configurations to automatically setup your particular system on a brand new computer. For example you could turn an old laptop into a server simply by cloning the configuration and deploying it. So I wanted to setup three different configurations:

• erebos - server
• pontos - laptop
• olympos - desktop

The names come from the greek mythology:

• erebos means hell in ancient greek and its user is Hades
• pontos means sea in ancient greek and its user is Poseidon
• olympos means olympus in ancient greek and its user is Zeus
• strategos means strategy in ancient greek and its user is Athena

Feel free to take a look at the configuration on Github

NOTE: For now the github repo is in private since some commits contain secrets

Installation

So, to make a NixOS configuration you need, NixOS ! So I've made a virtual machine and the installation can be done through a GUI or a command line. Nothing changes just take whatever you like. You can follow the installtion guide there: https://nixos.wiki/wiki/NixOS_Installation_Guide

To install one of my configurations:

# Make disk partitioning. Some hosts do not have disko enabled
sudo nix --experiemntal-features "nix-command flakes" run github:nix-community/disko -- --mode disko ./hosts/<erebos|pontos|olympos>/disko.nix

# Install system
sudo nixos-install --flake .#<erebos|pontos|olympos>

NOTE: I'm using nix flakes to backup the configuration on gihtub

Here is the directory structure:

nix/
├── flake.lock
├── flake.nix
│── configuration.nix
│── disko.nix
│── hardware-configuration.nix
│── home.nix
│── secrets.nix
├── readme.md
│── home-manager/
│   └── ...
│   sys/
│   ├── containers/
│   │   └── ...
│   ├── programs/
│   │   └── ...
│   ├── services/
│   │   └── ...
│   └── vars.nix
├── modules/
│   └── ...
└── secrets/
    └── ...

Software development

One benefit of NixOS is to declaratively describe development environments. Like everything else in NixOS there are two main ways to do this. Flakes and Channels. Since I'm using flakes for my system configuration I will also use them for my projects. Environments are declared in a flake.nix file. This file define not only the development environment but also how to compile and deploy your project under NixOS.

# flake.nix
{
	inputs = {
		nixpkgs.url = "github:nixos/nixpkgs/release-25.05";
		# Other system dependencies...
	};
	outputs = { nixpkgs, ... }@inputs:
	let
		system = "x86_64-linux";
		lib = nixpkgs.lib;
		pkgs = import nixpkgs {
			system = "${system}";
		};
	in {
		devShells.${system}.default = {
            # Your default dev env
		};
        devShells.${system}.node = {
            # Your node dev env
        };
	};
}

Here you can see that we just added nodejs you could add all the nixpkgs repo in there.

Finally, to enter you new dev environment just type this command:

nix develop .
# or for a particular env
nix develop .#node

For ease of use you can also use direnv. This will automatically enable a dev environment if declared if a .envrc file is present in your project directory.

echo 'use flake' > .envrc
direnv allow .