Nix Configuration

Unified NixOS and macOS (nix-darwin) configuration for personal systems.

Prerequisites

• Nix with flakes and commands enabled
• Git

macOS Setup (nix-darwin)

1. Install Xcode command line tools (if not already installed):

   xcode-select --install
   # If already installed, you may see: "command line tools are already installed"
   

2. Install Nix:

   curl -L https://install.determinate.systems/nix | sh -s -- install --prefer-upstream-nix
   

3. Restart shell or source profile:

   source /nix/var/nix/profiles/*/etc/profile.d/nix-daemon.sh
   

4. Generate SSH key and add to Forgejo:

   ssh-keygen -t ed25519 -C "s4mxdhid@zurimail.org"
   # Add pub key to http://minerva.lan:8080/user/settings/keys
   

5. Clone the config:

   git clone ssh://forgejo@minerva.lan/s4mxdhid/nixos-config.git
   cd nixos-config
   

6. Bootstrap nix-darwin:

   sudo --set-home nix run nix-darwin/master#darwin-rebuild -- switch --flake .#<hostname>
   

Change hostname:

sudo scutil --set HostName <new_name>
sudo scutil --set LocalHostName <new_name>
sudo scutil --set ComputerName <new_name>

After bootstrapping, darwin-rebuild will be available in your PATH:

sudo darwin-rebuild switch --flake .#$(scutil --get LocalHostName)

Structure

nix-config/
├── flake.nix              # Root flake - exports all host configurations
├── modules/               # Shared modules
│   └── darwin/           # Shared macOS configuration
│       ├── default.nix   # Main shared config
│       └── netbird.nix   # NetBird service
├── hosts/                # Host-specific configurations
│   ├── ares/             # MacBook Air M2 (macOS)
│   ├── vulcan/           # Mac Mini M4 (macOS)
│   ├── mars/             # MacBook Air M2 (omarchy)
│   └── minerva/          # AOOSTAR server (NixOS)
├── home/                 # Shared Home Manager configuration
│   ├── home.nix          # Main HM config with cross-platform imports
│   └── programs/         # Program-specific HM modules
└── programs/             # (legacy home modules directory)

Hosts

Host	OS	Description
ares	macOS	MacBook Air M2 - laptop
vulcan	macOS	Mac Mini M4 - desktop
mars	omarchy	MacBook Air M2 (TODO)
minerva	NixOS	AOOSTAR N1 Pro

Building

macOS (ares/vulcan)

sudo darwin-rebuild switch --flake .#$(scutil --get LocalHostName)

NixOS (minerva)

sudo nixos-rebuild switch --flake .#$(hostname)

Update flake inputs

nix flake update

Garbage collection

# macOS & NixOS
sudo nix-collect-garbage --delete-older-than 7d

Shared Configuration

Home Manager

Home Manager manages user-level packages and configurations for all hosts:

• Cross-platform: git, zsh, starship, mise, atuin, fzf, zoxide, yazi, zellij, btop, bottom, localsend, espanso, jujutsu, delta
• macOS-only: aerospace (disabled), sketchybar (disabled), paneru (window manager with gestures)

Darwin Modules

modules/darwin/ contains shared macOS configuration imported by both ares and vulcan:

• Homebrew packages and casks
• System defaults (Dock, Finder, etc.)
• Window managers (paneru)
• NetBird service

NetBird Setup

NetBird is configured to auto-connect on macOS hosts.

Setup for new machines:

1. Get a setup key from your NetBird admin dashboard

2. Create the setup key file:

   echo 'YOUR_NETBIRD_SETUP_KEY' > ~/.netbird_setup_key
   

3. Rebuild the system:

   sudo darwin-rebuild switch --flake .#$(scutil --get LocalHostName)
   

The activation script will automatically connect NetBird using the setup key.

Adding a New Host

macOS

1. Copy an existing host directory:

   cp -r hosts/ares hosts/new-host
   

2. Update hosts/new-host/configuration.nix comment (line 7)

3. Add to flake.nix:

   darwinConfigurations."new-host" = nix-darwin.lib.darwinSystem {
     specialArgs = { inherit inputs; };
     modules = [
       ./hosts/new-host/configuration.nix
       # ... other modules
     ];
   };
   

4. Update README.md with the new host

NixOS

1. Create directory: hosts/new-host/
2. Copy configuration.nix and hardware-configuration.nix from existing NixOS host
3. Update hostname in configuration
4. Add to flake.nix under nixosConfigurations
5. Update README.md

Clone the Repository (New Machine)

If setting up a new machine to use this config from the local Forgejo instance:

1. Generate an SSH key on the new PC: ssh-keygen -t ed25519 -C "s4mxdhid@zurimail.org"
2. Add the public key to Forgejo at <http://minerva.lan:8080/user/settings/keys>
3. Then clone with: git clone ssh://forgejo@minerva.lan/s4mxdhid/nixos-config.git

Troubleshooting

Build fails with "No space left on device"

sudo nix-collect-garbage --delete-older-than 7d

Cask installation fails (mv: cannot overwrite non-directory)

This error occurs when there's a stale cask directory in the Homebrew cache. The app may have been manually installed or the cache is corrupted.

# Replace 'app-name' with the failing cask (e.g., ungoogled-chromium)
rm -rf /opt/homebrew/Caskroom/app-name
rm -rf /Applications/AppName.app

Then rebuild:

sudo darwin-rebuild switch --flake .#$(scutil --get LocalHostName)

Build fails with stale inputs

nix flake update

Home Manager packages not appearing

Make sure home-manager module is included in the host's flake configuration.

Paneru not starting

Check that ~/.paneru.toml exists:

ls -la ~/.paneru.toml

If missing, rebuild the system to regenerate.

Secrets (sops-nix)

To encrypt secrets with sops:

# Generate age key (one-time setup)
mkdir -p ~/.config/sops/age
age-keygen -o ~/.config/sops/age/keys.txt
age-keygen -Y ~/.config/sops/age/keys.txt  # shows public key

# Add public key to .sops.yaml
# keys: - &pubkey AGE_PUBLIC_KEY_HERE

# Encrypt secrets.yaml
sops --encrypt --in-place secrets.yaml

# Edit encrypted file
sops secrets.yaml

The encrypted file can be committed to the repo safely.

Notes

• .DS_Store files are gitignored
• Comments in Nix files are preserved
• nixfmt can be used to format Nix files: nixfmt ~/.config/nix/*.nix

Permission fix

sudo chown -R root:nixbld /nix
sudo chmod -R 755 /nix/store
sudo chmod -R 1777 /nix/var/nix/temproots
sudo pkill nix-daemon
nix-collect-garbage
nix flake update