NixOS on Virtual Machine Config

Inspired by mitchellh config

VM Setup

The choice of VM software (VMware Fusion) is just about stability, reliability, and robust graphics support.

Manual Steps:

• assumes you have VM software installed
• note: copy/paste between host and guest does not work with Wayland guest desktops
• download the official NixOS image aarch64 ISO
• start creating a VM from this ISO
• keyboard profile - remove most of the shortcuts
• set up the required amount of CPU and RAM, enable 3D graphics acceleration, and enable Retina resolution
• set up the required amount of storage; I keep NVMe in the advanced settings
• network adapter shared with Mac
• remove audio and camera (if you don't need them)

Still manual steps, but inside the booted VM console:

• set a temporary root password (we need it to SSH into the VM; by default, neither the nixos nor the root user has a password)

$ sudo -i
$ passwd

• identify the installation disk with lsblk; for my VM, it is /dev/nvme0n1
• get your VM's IP address with ip a
• you may want to skim through the Makefile before proceeding

Bootstrap VM

Here I want to diverge from Mitchell's two-step bootstrap process and try to make a full fresh install from a flake. Conceptually, it looks like the flowchart below. Set system.stateVersion to the NixOS release initially installed and do not change it during routine upgrades; it does not need to match the installer ISO.

This Makefile and configuration are intentionally opinionated. If you clone or fork this repository, update the user, hostname, timezone, and openssh.authorizedKeys.keys in nixos/hosts/vm/default.nix. User configuration lives in nixos/home/alex/default.nix, with the Home Manager user wired up in nixos/flake.nix. Update the checkout and wallpaper paths in nixos/home/alex/desktops/noctalia/config.toml to match your setup.

Run the bootstrap from your Mac, replacing the address and disk as needed:

make vm/fresh \
  NIXADDR=192.168.64.10 \
  NIXDISK=/dev/nvme0n1 \
  CONFIRM_ERASE=YES

The selected disk will be completely erased. The Make target sends scripts/prepare-vm.sh to Bash in the live installer to check connectivity, partition, format, mount, and generate the hardware configuration. It then uploads the flake and installs NixOS. The process is:

make vm/fresh
 │
 ├── SSH into installer
 │
 ├── partition / format / mount
 │
 ├── nixos-generate-config --root /mnt
 │
 ├── copy my Nix flake into /mnt
 │
 ├── nixos-install --flake ...#vm --no-root-passwd
 │
 ├── reboot
 │
 └── hopefully done!

After the Bootstrap

Our user has no password yet and can initially access the VM only through SSH using a private key matching openssh.authorizedKeys.keys. Run ssh username@hostname.local, or use ssh -i /path/to/private-key username@hostname.local for a non-standard key location, then set the password with sudo passwd username. Password SSH remains disabled by this configuration.

Set up the working checkout

/nixos-config is the bootstrap copy. Everyday edits and rebuilds use the Git checkout at /home/alex/Projects/nixos-vm, whose flake is in the nixos/ subdirectory. Noctalia's status plugin also uses this flake directory.

On the VM, as alex, clone the repository and copy the installed configuration into it once:

mkdir -p ~/Projects
git clone https://github.com/mindnbytes/nixos-vm.git ~/Projects/nixos-vm
rsync -rv /nixos-config/ ~/Projects/nixos-vm/nixos/
cd ~/Projects/nixos-vm
git diff -- nixos/

This preserves the configuration used for installation, including nixos/hosts/vm/hardware-configuration.nix with this VM's generated filesystem UUIDs. Review and commit the imported changes. From this point onward, the checkout is the source of truth; /nixos-config is no longer used for rebuilds.

Everyday workflow

Edit system settings in nixos/hosts/vm/ and user settings in nixos/home/alex/. Stage any new configuration files with git add so the Git-backed flake can see them. From the VM's flake directory:

cd ~/Projects/nixos-vm/nixos
nix flake check --no-build
noctalia config validate home/alex/desktops/noctalia
sudo nixos-rebuild switch --flake .#vm

nix flake check --no-build checks evaluation; the rebuild also validates Niri's configuration before activation. Home Manager is integrated into the system rebuild. See the desktop READMEs for how Noctalia's writable colors and GUI overrides interact with the checked-in settings.

After verifying the result, review git diff and commit the intended changes. To update pinned dependencies, run nix flake update in the flake directory, then follow the same validation and rebuild steps and commit flake.lock.

Helix and Zed use this VM's working flake at ~/Projects/nixos-vm/nixos for nixd's package and NixOS/Home Manager option completions, independently of the editor's working directory. These are global editor defaults: other projects also use the VM's completion context unless overridden. If you relocate the checkout, update the path in both editor modules and Noctalia's config.toml.

Copy configuration back to the Mac

From the repository on the Mac:

make vm/sync NIXADDR=dev.local
git diff -- nixos/

vm/sync copies the VM's working ~/Projects/nixos-vm/nixos/ directory into the local nixos/ directory. It overwrites matching files and adds new ones, but does not propagate deletions or copy Git history. Review the diff and git status, and apply any intended deletions locally.