Nix Configurations

Flake-based NixOS and Home Manager configurations for multiple personal machines.

Repository Structure

• flake.nix: Declares inputs (nixpkgs, home-manager, nixos-hardware) and outputs for NixOS and Home Manager configurations
• hostnames/: Per-host NixOS configurations
  • hostnames/modules/: Reusable NixOS modules (networking, locales, desktop environments, etc.)
  • hostnames/<hostname>/: Host-specific configuration and hardware profiles
• home/: Home Manager configurations
  • home/modules/: Reusable user-space modules (git, bash, ssh, tmux, etc.)
  • home/joonas/: Per-host Home Manager configs for the joonas user

Quick Start

Building a NixOS Configuration

nix rebuild switch --flake .#<HOSTNAME>

Replace <HOSTNAME> with your target machine (e.g., joonas-linux).

Applying Home Manager Changes

home-manager switch --flake .#joonas@<HOSTNAME>

Updating Dependencies

nix flake update

Review the flake.lock diff before committing.

Adding a New Host

1. Generate hardware configuration:

   nixos-generate-config --root /mnt --show-hardware-config > hostnames/<new-host>/hardware-configuration.nix

2. Create hostnames/<new-host>/configuration.nix importing desired modules from hostnames/modules/

3. Add entries to flake.nix:

   • nixosConfigurations.<new-host> using nixosSystemFor
   • homeConfigurations."joonas@<new-host>" using homeManagerConfigurationFor

4. Set appropriate system.stateVersion and home.stateVersion

Module Organization

NixOS Modules (hostnames/modules/)

• common.nix: Base system packages, fonts, sudo, and nix daemon settings
• locales.nix: Timezone and locale configuration
• networking.nix: NetworkManager and firewall defaults
• cosmic.nix, gnome.nix, kde.nix, hyprland.nix: Desktop environment stacks

Home Manager Modules (home/modules/)

Focused modules for individual tools:

• git.nix: Git identity and aliases
• bash.nix, zsh.nix: Shell configuration
• ssh.nix: SSH client settings
• tmux.nix: Terminal multiplexer config

Best Practices

• Keep secrets out of the repository; use environment variables or external secret management
• Enable unfree packages explicitly per host with nixpkgs.config.allowUnfree = true
• Import only the modules you need in each host configuration
• Comment optional feature imports in host configs for documentation
• Use nixos-hardware profiles for tested hardware configurations
• Test configuration changes in a VM before deploying to production machines

Home Manager Installation

If Home Manager is not yet available:

nix-channel --add https://github.com/nix-community/home-manager/archive/master.tar.gz home-manager
nix-channel --update
export NIX_PATH=$HOME/.nix-defexpr/channels${NIX_PATH:+:}$NIX_PATH
nix-shell '<home-manager>' -A install
. "$HOME/.nix-profile/etc/profile.d/hm-session-vars.sh"

Then apply your configuration:

home-manager switch --flake .#joonas@<HOSTNAME>