NixOS Configuration Repository

🚀 Overview

After using Arch Linux for a long time I got to know NixOS and decided to give it a try. This repository contains my complete, version-controlled configuration for it.

The goal of this repository is to provide a fully reproducible and declarative environment setup. By managing my system configuration entirely through Nix expressions, I ensure that my machine state can be reliably reproduced on any hardware, minimizing the risk associated with manual changes and drift over time.

✨ Key Features

1. Declarative Management: Every aspect of the system—from desktop environment packages (e.g., Wayland compositors, window managers) to service settings (e.g., SSH keys, firewalls)—is defined in code (.nix files).
2. Reproducibility: Running nixos-rebuild with this configuration ensures that the entire system state is reproducible and consistent across rebuilds.
3. Version Control: Changes are tracked via Git, allowing for easy rollback to previous stable states and meticulous auditing of system modifications.
4. Multi Hardware Support: One central configuration, which supports multiple computers and notebooks.

⚙️ Getting Started

To deploy this configuration onto a NixOS machine, follow these general steps:

1. Create User Configuration Folder

   mkdir ~/.config/nixos

2. Clone the Repository

   • Enter a nix-shell with git:

   nix-shell -p git

   • Inside the nix-shell switch to the configuration folder and clone the repository:

   cd ~/.config/nixos
   git clone https://github.com/elmurato/nixos-cfg.git .

3. Adapt User Name

   • Search for elmurato in configuration.nix and home-manager.nix and replace it with your own username.

4. Remove Default Configuration and Create Symlink

   ⚠️ Warning: This permanently deletes /etc/nixos. If you have existing configuration files you want to keep, back them up first:

   cp -r /etc/nixos ~/nixos-backup

   sudo rm -r /etc/nixos
   sudo ln -s ~/.config/nixos /etc/nixos

5. Select Hardware, Rebuild and Apply

   • On first rebuild, pass the hostname of the target hardware. Example ThinkPad P14s Gen2i:

   sudo nixos-rebuild switch --flake /etc/nixos#thinkpad-p14s-gen2i

   • Once the hostname is set, rebuild as usual from that point on:

   sudo nixos-rebuild switch --flake /etc/nixos

📂 Repository Structure

nixos-cfg/
├── configuration.nix
├── flake.nix
├── flake.lock
├── home-manager.nix
└── hosts/
    ├── thinkpad-p14s-gen2i/
    │   ├── default.nix
    │   └── hardware-configuration.nix
    └── nixos-vm/
        ├── default.nix
        └── hardware-configuration.nix

File / Directory	Description
configuration.nix	Primary system configuration. Defines global OS settings: networking, user accounts, installed packages, kernel options, and services. Main entry point for nixos-rebuild.
flake.nix	Flakes entry point. Declares all external inputs (e.g., nixpkgs, home-manager) and exposes the NixOS configurations for each host as outputs. Replaces the traditional nix-channel approach.
flake.lock	Auto-generated lock file that pins every flake input to an exact git revision, guaranteeing fully reproducible builds across machines and time. Do not edit manually.
home-manager.nix	User-specific configuration. Manages shell settings (Oh My Zsh, aliases), user-scoped applications, desktop customizations (GTK themes, terminal emulator), and dotfiles.
hosts/thinkpad-p14s-gen2i/default.nix	Hardware-specific customizations for the ThinkPad P14s Gen2i.
hosts/thinkpad-p14s-gen2i/hardware-configuration.nix	Auto-generated hardware configuration for the ThinkPad P14s Gen2i.
hosts/nixos-vm/default.nix	Hardware-specific customizations for the VM.
hosts/nixos-vm/hardware-configuration.nix	Auto-generated hardware configuration for the VM.