Forrest Jacobs

NixOS on WSL

I recently set up a new Windows machine for gaming, but I’m actually using it more to play around with Linux via WSL. I set up NixOS on WSL using the aptly named NixOS on WSL project, but ran into a few issues during setup that bricked my environment1. Below are the steps that ended up working for me in the end:


Step 1: Install WSL 2

Per Microsoft’s documentation:

  1. Open PowerShell as an admin by right-clicking on it and selecting “Run as administrator.”

  2. Run wsl --install

Step 2: Install NixOS

Per NixOS-WSL’s documentation:

  1. Download the installer listed in NixOS-WSL’s 22.05 release.

  2. Move the file where you want your NixOS installation to live. I put it in C:\Users\<my username>\AppData\Local\NixOS, which I think follows Windows’s conventions.

  3. Open PowerShell as a normal user, change to the directory you just made, and run wsl --import NixOS . nixos-wsl-installer.tar.gz --version 2

  4. Run wsl -d NixOS to start NixOS. It’ll run through initial setup, then hang on “Starting systemd…” Press Ctrl + C to get back to PowerShell, and then run wsl --shutdown followed by wsl -d NixOS to get back into NixOS.

Step 3: Configure NixOS

At this point you should have a basic NixOS 22.05 installation! Let’s finish up by setting a username, switching over to flakes, updating to NixOS 22.11, and enabling native systemd:

  1. Edit /etc/nixos/configuration.nix and make the following changes. Use sudo or some such to edit the file as root. You may want to nix-shell -p your favorite editor at this point – maybe Helix?

    • Change wsl.defaultUser to your desired username, and add something like users.users.<your username>.isNormalUser = true;
    • Remove references to ./nixos-wsl since we’ll set NixOS-WSL as a flake input:
        { lib, pkgs, config, modulesPath, ... }:
      - with lib;
      - let
      -   nixos-wsl = import ./nixos-wsl;
      - in
          imports = [
      -     nixos-wsl.nixosModules.wsl
    • Add wsl.nativeSystemd = true;
    • Add networking.hostName, and set it to your Windows 11 “Device name.” You can find this in the Windows Settings app under System > About.
  2. Add /etc/nixos/flake.nix as root with contents like the following. Replace <host-name> with your actual host name from configuration.nix.

      inputs = {
        nixpkgs.url = "github:NixOS/nixpkgs/nixos-22.11";
        NixOS-WSL = {
          url = "github:nix-community/NixOS-WSL";
          inputs.nixpkgs.follows = "nixpkgs";
      outputs = { self, nixpkgs, NixOS-WSL }: {
        nixosConfigurations."<host-name>" = nixpkgs.lib.nixosSystem {
          system = "x86_64-linux";
          modules = [
            { nix.registry.nixpkgs.flake = nixpkgs; }
  3. Run sudo nixos-rebuild switch

  4. exit out of NixOS, then run wsl --shutdown followed by wsl -d NixOS. You should be logged in as the new default user.

  5. At this point you should have a stable base to make any configuration changes you’d like.

Step 4: Cleaning up

Addendum: Share .ssh directory with Windows

It turns out that file permissions set in WSL are preserved in NTFS2. You can store your SSH configuration files in Windows, and still use them from WSL with no permissions issues:

That’s it! You can verify that permissions carried over with ls -al ~/.ssh/

Addendum: Set up fish in NixOS the right way

I use fish as my shell, but when I set it up in WSL I started getting errors like this:

fish: Unknown command: ls
/nix/store/lkf5vmavnxa0s37imb03gv7hs6dh5pll-fish-3.5.1/share/fish/functions/ (line 64):
    command $__fish_ls_command $__fish_ls_color_opt $opt $argv
in function 'ls'

Uh oh. Obviously, there are important directories missing from my path. It turns out that I was missing some configuration3:

{ = true;

I don’t know why this issue only appeared in WSL, but fish users should probably set in NixOS whether the issue appears or not.

See also

  1. I think I changed the default user without actually setting up that user? Or I switched to native systemd before upgrading to a version of NixOS on WSL that supports it? ↩︎

  2. Thanks to this Stack Exchange answer for pointing me in the right direction. You don’t have to follow the instructions in this post – NixOS on WSL already mounts Windows’s drives with the necessary options. ↩︎

  3. Thanks to this GitHub issue for alerting me to the problem. ↩︎