Nix Configuration#

v0.5.0

Personal NixOS and nix-darwin configurations for managing multiple machines with a unified, centralized setup.

Note: This is a personal configuration repository. While you're welcome to use it as reference, it's specifically tailored to my needs and setup.

🎯 Quick Start for Forkers: Edit modules/options.nix to customise everything — username, email, git settings, desktop theme, packages, and more. Per-host overrides go in hosts/<hostname>/default.nix.

Key Features#

✨ Centralized Configuration — All option defaults in modules/options.nix (single source of truth) 🔄 DRY Principles — Zero duplication; the NixOS module system handles everything 🎯 Easy Customization — Change any default in one file, applies everywhere 📦 Multi-System — Unified config for NixOS and macOS 🏠 Unified Home Manager — Same shell, git, SSH config across all systems 🔐 Secrets Management — Encrypted secrets with sops-nix 🗺️ Infrastructure Diagrams — Auto-generated topology SVGs via nix-topology 🛠️ Rust Tools — health-check, flake-bump, gen-diff maintenance utilities

Managed Systems#

macOS (nix-darwin) — PRIMARY#

• macmini — Apple Silicon Mac Mini (M2, 16 GB) — Main daily driver

Linux (NixOS) — SECONDARY#

• laptop — Dell Inspiron 3501 with KDE Plasma 6 — Secondary workstation
• server — Minimal headless server — Bluesky PDS, Forgejo, Nextcloud, Immich, Jellyfin, Cloudflare tunnel + hardened security

Configuration Architecture#

All options are declared with typed defaults in modules/options.nix. Every system module reads values via config.myConfig.*; home-manager modules use osConfig.myConfig.*. No custom abstraction layer — it's plain NixOS module system.

To change a value for all hosts:

# modules/options.nix
timeZone = mkOption {
  type = str;
  default = "Europe/London";  # ← change here
};

To override for one host:

# hosts/laptop/default.nix
myConfig.gaming.enable = true;
myConfig.isDesktop     = true;

See lib/USAGE.md for patterns used in modules.

Quick Start#

Prerequisites#

• NixOS: Install NixOS on your system
• macOS: Install Nix via the Determinate Nix Installer

Initial Setup#

mkdir -p ~/.config
curl -L \
  https://github.com/ewanc26/nix/archive/refs/heads/main.tar.gz \
  | tar -xz -C ~/.config
mv ~/.config/nix-main ~/.config/nix-config
cd ~/.config/nix-config

Building#

NixOS:

sudo nixos-rebuild switch --flake .#laptop
sudo nixos-rebuild switch --flake .#server

macOS (first time):

sudo nix run nix-darwin -- switch --flake .#macmini

macOS (subsequent):

sudo darwin-rebuild switch --flake .#macmini

Infrastructure Diagrams#

Uses nix-topology to automatically generate SVG diagrams of the infrastructure from the NixOS configurations. Physical connections and networks that can't be inferred automatically are defined in topology.nix.

Render the diagrams (must run on Linux — SSH to the server or use a remote builder):

# On the server:
ssh server
nix build ~/.config/nix-config#topology.x86_64-linux.config.output

# Or from macOS with the server as a remote builder:
nix build .#topology.x86_64-linux.config.output \
  --builders 'ssh://server x86_64-linux'

This produces two diagrams:

• main.svg — physical host/interface layout
• network.svg — network-centric view showing which hosts share which networks

Updating topology:

Edit topology.nix to reflect physical changes (new cables, new networks, etc.). Service and interface information is extracted automatically from the NixOS configs.

Customization#

All defaults live in modules/options.nix — one option block per domain.

# Examples of what to edit
nano modules/options.nix           # Username, timezone, packages, themes, etc.
nano hosts/laptop/default.nix      # Enable gaming, desktop mode, etc.
nano hosts/server/default.nix      # Enable server services
nano topology.nix                  # Physical network connections
nano settings/darwin/default.nix   # macOS Dock, Finder, trackpad
nano settings/plasma/default.nix   # KDE Plasma layout and behaviour

See docs/settings.md for the full guide and docs/settings-config.md for the complete option reference.

Maintenance#

Health Check (Recommended Before Building)#

health-check

Update Flake Inputs#

nix flake update
# or selectively
flake-bump

Garbage Collection#

# Runs automatically weekly (configured in modules/common.nix)
cleanup

Secrets Management#

Uses sops-nix with age encryption.

• Secrets are encrypted with age using the host's SSH ed25519 host key
• Encrypted files in secrets/ are safe to commit
• The key inventory and creation rules are in .sops.yaml
• Decrypted at activation via /etc/ssh/ssh_host_ed25519_key

See docs/secrets.md for full details.

Adding a New Host#

See docs/hosts.md. Quick summary:

1. Create hosts/YOUR-HOSTNAME/default.nix
2. Generate hardware config: nixos-generate-config --show-hardware-config
3. Add entry to flake.nix → nixosConfigurations
4. Add the host's interfaces/connections to topology.nix
5. Build: sudo nixos-rebuild switch --flake .#YOUR-HOSTNAME

Inputs#

Unified Configuration Benefits#

Same Shell Everywhere#

• zsh with identical aliases, history, and key bindings on all systems
• SSH client configuration unified (connection multiplexing, agent integration)
• Git settings consistent across NixOS and macOS
• Starship prompt looks the same everywhere
• Ghostty terminal configured identically on Linux and macOS

Platform-Specific When Needed#

• macOS: SSH keys loaded at login via LaunchAgent (ssh-add --apple-load-keychain)
• Linux desktop: SSH keys loaded at login via systemd + ksshaskpass/KWallet
• Server: No agent needed — SSH connections go into it, not out
• KDE Plasma settings only apply on Linux desktop
• Homebrew only on macOS

Documentation#

Core Documentation#

• lib/USAGE.md — module patterns for developers
• docs/settings.md — how configuration works (start here)
• docs/settings-config.md — full option reference
• docs/REFERENCE.md — quick-reference command card

Host Management#

• docs/hosts.md — hosts documentation index
• docs/hosts-overview.md — complete comparison of all three hosts
• docs/hosts-modification.md — how to modify and add hosts
• docs/hosts-laptop.md — Dell Inspiron 3501 (NixOS + KDE Plasma 6)
• docs/hosts-server.md — headless server setup
• docs/hosts-macmini.md — macOS with nix-darwin
• docs/TAILSCALE-SSH.md — inter-host SSH over Tailscale

Settings Management#

• docs/settings.md — settings overview
• docs/settings-structure.md — why the config is modular
• docs/secrets.md — secrets management

☕ Support#

If you found this useful, consider buying me a ko-fi!