NixOS Dual-Configuration Setup

A NixOS system with two fully isolated configurations:

1. Dev - Latest stable kernel, web development tooling (Docker, Node.js, direnv)
2. Gaming - Zen kernel, Steam, Lutris, performance tools

Both share a common base: MangoWC (Wayland compositor) + Noctalia Shell, AMD RDNA 4 GPU support, and a shared /home directory with mutable dotfiles.

Target Hardware

Component	Model	Notes
CPU	AMD Ryzen 7 5700G	Zen 3, iGPU available
GPU	AMD RX 9060 XT	RDNA 4, requires Kernel 6.14+, Mesa 25.0+
Motherboard	MSI B550 Tomahawk	Excellent IOMMU groups

Directory Structure

nixos-config/
├── flake.nix                           # Main flake definition
├── flake.lock                          # Auto-generated after first build
├── hosts/
│   └── <hostname>/
│       └── hardware-configuration.nix  # Copy from /etc/nixos/
└── modules/
    ├── common.nix                      # Shared configuration
    ├── dev.nix                         # Development profile
    └── gaming.nix                      # Gaming profile

Prerequisites

1. NixOS installed (minimal install is fine)
2. Flakes enabled in existing config or via: nix-shell -p nixFlakes
3. Know your hostname, username, timezone, and locale

Quick Setup

1. Clone and Prepare

# Clone this repo to your config directory
git clone <this-repo> ~/nixos-config
cd ~/nixos-config

# Create the host directory (replace <hostname> with your actual hostname)
mkdir -p hosts/<hostname>

# Replace the placeholder hardware-configuration.nix with your actual one
cp /etc/nixos/hardware-configuration.nix hosts/<hostname>/

2. Review Configuration Defaults

Defaults are set in flake.nix and used across modules. Update them there:

Setting	Example Value	File
hostname	desktop	flake.nix
username	john	flake.nix
time.timeZone	America/New_York	modules/common.nix
i18n.defaultLocale	en_US.UTF-8	modules/common.nix

Update the hostname value in flake.nix to match your machine. Then rename the default hosts/atlas/ directory to the same value (e.g., hosts/desktop/). The flake uses it to locate hosts/<hostname>/hardware-configuration.nix.

3. Stage Files in Git

IMPORTANT: Flakes require all files to be tracked by git before building.

cd ~/nixos-config
git add .

4. Verify Flake

nix flake check
nix flake show

5. Build and Switch

IMPORTANT: Ensure all files are staged in git (step 3) before building.

# Build and switch to dev config as main system profile
sudo nixos-rebuild switch --flake .#dev

# (Optional) Test gaming config without committing it as a boot option
sudo nixos-rebuild test --flake .#gaming

# Build gaming config as separate boot profile (available after next reboot)
sudo nixos-rebuild boot --profile-name gaming --flake .#gaming

6. Reboot and Verify

Boot menu should show:

• NixOS (dev) - Default boot
• NixOS (gaming, zen) - Gaming profile

Updating

IMPORTANT: Always update both profiles together to avoid kernel/Mesa version drift.

After Configuration Changes

cd ~/nixos-config
git add .  # Stage your configuration changes
sudo nixos-rebuild switch --flake .#dev
sudo nixos-rebuild boot --profile-name gaming --flake .#gaming

Updating Flake Inputs Only

nix flake update
git add flake.lock  # Only stage the lock file, not other changes
sudo nixos-rebuild switch --flake .#dev
sudo nixos-rebuild boot --profile-name gaming --flake .#gaming

Configuration Summary

Config	Kernel	Key Features
dev	Latest	Docker, Node.js, direnv, dev CLI tools
gaming	Zen	Steam, Lutris, MangoHUD, Gamemode, CoreCtrl
Shared	-	MangoWC, Noctalia, AMD GPU, PipeWire, Firefox

Post-Installation

Change Password

Generate a password hash and save it to /etc/nixos/secrets/<username>/password.hash (replace <username> with your actual username):

sudo mkdir -p /etc/nixos/secrets/<username>
sudo chmod 700 /etc/nixos/secrets/<username>
mkpasswd -m sha-512 | sudo tee /etc/nixos/secrets/<username>/password.hash
sudo chmod 600 /etc/nixos/secrets/<username>/password.hash

Setup MangoWC

MangoWC is configured to auto-start via greetd. To customize it:

mkdir -p ~/.config/mango
cp /etc/mango/config.conf ~/.config/mango/config.conf

# Create autostart script for Noctalia shell
cat > ~/.config/mango/autostart.sh << 'EOF'
#!/bin/bash
# Ensure quickshell is in PATH (it should be as a user package)
qs -c noctalia-shell &
EOF
chmod +x ~/.config/mango/autostart.sh

Add to ~/.config/mango/config.conf:

exec-once="~/.config/mango/autostart.sh"

Dev Profile: Docker Access

After switching to the dev profile for the first time, you must log out and log back in (or reboot) for Docker group membership to take effect.

Auto-start MangoWC from TTY (Alternative)

If not using greetd, add to ~/.bash_profile or ~/.zprofile:

if [[ -z $WAYLAND_DISPLAY ]] && [[ $(tty) == /dev/tty1 ]]; then
    exec mango
fi

GPU Verification

# Verify firmware loaded
dmesg | grep -i "amdgpu" | grep -i "firmware"

# Check GPU detected
lspci | grep VGA

# Verify Vulkan
vulkaninfo | head -30

# Check ray tracing support
vulkaninfo | grep VK_KHR_ray_tracing_pipeline

# Verify OpenCL
clinfo | head -20

Troubleshooting

Flake can't find files

git add .  # Flakes require files to be tracked by git

MangoWC doesn't start

systemctl status seatd
groups  # Ensure user is in 'seat' group

RDNA 4 black screen

dmesg | grep -i "amdgpu" | grep -i "firmware"
uname -r  # Should be 6.14+

Steam doesn't launch

Ensure hardware.graphics.enable32Bit = true; in common.nix.

Games won't launch

cat /proc/sys/vm/max_map_count  # Should be 2147483642 on gaming profile

License

MIT