macOS Nix Configuration

This repository setup a new macOS using nix-darwin and flakes.

🛠 Initial Setup/Reinstall

1. Install Nix

   Ref: https://github.com/DeterminateSystems/nix-installer

   curl -fsSL https://install.determinate.systems/nix | sh -s -- install
   

   If the first run fails, try running it again.

2. Install xcode-select

   Required by Homebrew later. Still requires a manual agreement to License.

   xcode-select --install
   softwareupdate -i -a --agree-to-license
   

3. Copy config files

   Copy is used here instead of clone. Init a repo to backup the final settings.

   mkdir -p ~/.config/nix-config && cd ~/.config/nix-config
   curl -L https://github.com/lcenchew/macnix/archive/main.tar.gz | tar -xz --strip-components=1
   

4. Setup Nix config

   Refresh the env to take in changes from Nix install. Then run the setup logic.

   exec zsh
   chmod +x setup
   ./setup
   

💾 External Storage Setup

For Mac Mini with 256G drive, attempt to install Nix to an external SSD Prepare the drive as follows before running above setup.

Create an external APFS Volume

1. List available drives to identify the external storage device identifier (e.g., disk3, disk4)

   diskutil list
   

2. Add an external APFS Volume named Nix Store

   Replace diskX with the actual identifier identified above.

   diskutil apfs addVolume diskX APFSX "Nix Store"
   

Force macOS to create a root /nix folder

macOS protects the root directory using Signed System Volumes (SSV). Use /etc/synthetic.conf to instruct the operating system kernel to spawn an empty root-level mount point on the next launch. (see man synthetic.conf)

1. Update /etc/synthetic.conf

   echo "nix" | sudo tee -a /etc/synthetic.conf
   

2. Reboot. Check. ls /

Map the External Volume in fstab

1. Get the Volume UUID

   diskutil info "Nix Store" | grep "Volume UUID"
   

2. Add volume to fstab

   Replace with the value found above.

   echo "UUID=<VOLUME UUID> /nix apfs rw,noatime,nobrowse,nosuid,owners,failok,late" | sudo tee -a /etc/fstab
   

3. Reboot. Check. df -h /nix

📁 File Structure

~/.config/nix-config

.
├── flake.nix          # Standardized to look for current-host.nix
├── common.nix         # Shared settings across all hardware type
├── macbook.nix        # Settings for macbook 
├── macmini.nix        # Settings for macmini
├── current-host.nix   # Created based on setup parameters (not committed, .gitignore)
└── setup              # The setup logic

❔ Nix vs Brew

• Nix: Use for shell, terminal tools (Git, Neovim, Python, Node), and system settings (Dock, Trackpad).
• Homebrew (via Nix): Use for GUI "Apps" normally found /Applications folder.

⚠️ Notes

• Experimental Features: This config enables nix-command and flakes by default.
• system.stateVersion: Do not update this value even when updating Nixpkgs. It represents the compatibility state of the system when first installed. Changing it may result in data migration issues.

🛠 Maintenance and Management

Some basics to maintain and manage the system after installing.

Update

• Determinate Nix See https://github.com/DeterminateSystems/nix-installer#upgrading-determinate-nix

  sudo determinate-nixd upgrade
  

• flake

  cd .config/nix-config
  sudo -H nix flake update
  sudo -H darwin-rebuild switch --flake .#current-host