Merge pull request #295 from nix-community/prep-release

New release preparation

Author: nzbr

.github/workflows/main.yml

@@ -50,6 +50,12 @@ jobs:
     needs:
       - prepare
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        config:
+          - modern
+          - legacy
+          - test
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -66,15 +72,17 @@ jobs:
           echo ${{ needs.prepare.outputs.version }} > ./VERSION
           echo $(git rev-parse HEAD) >> ./VERSION
 
-      - name: Build installer 🛠️
+      - name: Build tarballs 🛠️
+        # We can't just nix run here because nix is not on root's PATH in the container
         run: |
-          nix build '.#nixosConfigurations.mysystem.config.system.build.installer'
+          nix build .#nixosConfigurations.${{ matrix.config }}.config.system.build.tarballBuilder
+          sudo ./result/bin/nixos-wsl-tarball-builder nixos-wsl.tar.gz
 
-      - name: Upload installer 📤
+      - name: Upload tarball 📤
         uses: actions/upload-artifact@v3
         with:
-          name: installer
-          path: result/tarball/nixos-wsl-installer.tar.gz
+          name: tarball-${{ matrix.config }}
+          path: nixos-wsl.tar.gz
 
   checks:
     name: Flake Check 📋
@@ -117,10 +125,10 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Download installer 📥
+      - name: Download tarball 📥
         uses: actions/download-artifact@v3
         with:
-          name: installer
+          name: tarball-test
 
       - name: Execute test 🧪
         shell: pwsh

.github/workflows/release.yml

@@ -14,13 +14,13 @@ jobs:
     name: Create Release 📢
     runs-on: ubuntu-latest
     steps:
-      - name: Download installer 📥
+      - name: Download tarball 📥
         uses: actions/download-artifact@v3
-        with:
-          name: installer
 
       - name: Generate checksums 🔑
         run: |
+          mv tarball-modern/nixos-wsl.tar.gz nixos-wsl.tar.gz
+          mv tarball-legacy/nixos-wsl.tar.gz nixos-wsl-legacy.tar.gz
           for x in *.tar.gz; do
             sha256sum $x > ${x}.sha256
           done
@@ -29,7 +29,9 @@ jobs:
         uses: softprops/action-gh-release@v1
         with:
           files: |
-            nixos-wsl-installer.tar.gz
-            nixos-wsl-installer.tar.gz.sha256
+            nixos-wsl.tar.gz
+            nixos-wsl.tar.gz.sha256
+            nixos-wsl-legacy.tar.gz
+            nixos-wsl-legacy.tar.gz.sha256
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.gitignore

@@ -1,3 +1,3 @@
 result
 result-*
-nixos-wsl-installer.tar.gz
+nixos-wsl*.tar.gz

README.md

@@ -9,18 +9,23 @@ A minimal root filesystem for running NixOS on WSL. It can be used with
 [DistroLauncher](https://github.com/microsoft/WSL-DistroLauncher) as
 `install.tar.gz` or as input to `wsl --import --version 2`.
 
+## System requirements
+
+NixOS-WSL is tested with the Windows Store version of WSL 2, which is now available on all supported Windows releases (both 10 and 11).
+Support for older "inbox" versions is best-effort.
+
 ## Quick start
 
-First, [download the latest release\'s installer](https://github.com/nix-community/NixOS-WSL/releases/latest).
+First, [download the latest release](https://github.com/nix-community/NixOS-WSL/releases/latest).
 
 Then open up a Terminal, PowerShell or Command Prompt and run:
 
 ```sh
-wsl --import NixOS .\NixOS\ nixos-wsl-installer.tar.gz --version 2
+wsl --import NixOS .\NixOS\ nixos-wsl.tar.gz --version 2
 ```
 
 This sets up a new WSL distribution `NixOS` that is installed under
-`.\NixOS`. `nixos-wsl-installer.tar.gz` is the path to the file you
+`.\NixOS`. `nixos-wsl.tar.gz` is the path to the file you
 downloaded earlier. You might need to change this path or change to the download directory first.
 
 You can now run NixOS:
@@ -29,11 +34,6 @@ You can now run NixOS:
 wsl -d NixOS
 ```
 
-The installer will unpack the file system and subsequently start NixOS.
-A few warnings about file systems and locales will pop up. You can
-safely ignore them. After systemd has started, you should be greeted
-with a bash prompt inside your fresh NixOS installation.
-
 If you want to make NixOS your default distribution, you can do so with
 
 ```sh
@@ -68,57 +68,34 @@ If you have a flakes-enabled Nix, you can use the following command to
 build your own tarball instead of relying on a prebuilt one:
 
 ```cmd
-nix build github:nix-community/NixOS-WSL#nixosConfigurations.mysystem.config.system.build.installer
+sudo nix run github:nix-community/NixOS-WSL#nixosConfigurations.modern.config.system.build.tarballBuilder
 ```
 
 Or, if you want to build with local changes, run inside your checkout:
 
 ```cmd
-nix build .#nixosConfigurations.mysystem.config.system.build.installer
+sudo nix run .#nixosConfigurations.your-hostname.config.system.build.tarballBuilder
 ```
 
 Without a flakes-enabled Nix, you can build a tarball using:
 
 ```cmd
-nix-build -A nixosConfigurations.mysystem.config.system.build.installer
-```
+nix-build -A nixosConfigurations.mysystem.config.system.build.tarballBuilder && sudo ./result/bin/nixos-wsl-tarball-builder
 
-The resulting installer tarball can then be found under
-`./result/tarball/nixos-wsl-installer.tar.gz`.
+```
 
-You can also build a rootfs tarball without wrapping it in the installer
-by replacing `installer` with `tarball` in the above commands. The
-rootfs tarball can then be found under
-`./result/tarball/nixos-wsl-x86_64-linux.tar.gz`.
+The resulting tarball can then be found under `nixos-wsl.tar.gz`.
 
 ## Design
 
 Getting NixOS to run under WSL requires some workarounds:
 
-### systemd support
-
-WSL comes with its own (non-substitutable) init system while NixOS uses
-systemd. Simply starting systemd later on does not work out of the box,
-because systemd as system instance refuses to start if it is not PID 1.
-This unfortunate combination is resolved in two ways:
-
-- the user\'s default shell is replaced by a wrapper script that acts
-    is init system and then drops to the actual shell
-- systemd is started in its own PID namespace; therefore, it is PID 1.
-    The shell wrapper (see above) enters the systemd namespace before
-    dropping to the shell.
-
-### Installer
-
-Usually WSL distributions ship as a tarball of their root file system.
-These tarballs however, can not contain any hard-links due to the way
-they are unpacked by WSL, resulting in an \"Unspecified Error\". By
-default some Nix-derivations will contain hard-links when they are
-built. This results in system tarballs that can not be imported into
-WSL. To circumvent this problem, the rootfs tarball is wrapped in that
-of a minimal distribution (the installer), that is packaged without any
-hard-links. When the installer system is started for the first time, it
-overwrites itself with the contents of the rootfs tarball.
+- instead of directly loading systemd, we use a small shim that runs the NixOS activation scripts first
+- some additional binaries required by WSL's internal tooling are symlinked to FHS paths on activation
+
+Running on older WSL versions also requires a workaround to spawn systemd by hijacking the root shell and
+spawning a container with systemd inside. This method of running things is deprecated and not recommended,
+however still available as `nixos-wsl-legacy.tar.gz` or via `wsl.nativeSystemd = false`.
 
 ## License
 

checks/username.nix

@@ -6,9 +6,9 @@
 
 let
   baseModule = { ... }: {
-    imports = [ ../configuration.nix ];
-
+    imports = [ ../modules ];
     wsl.enable = true;
+    wsl.defaultUser = "nixos";
   };
   changedUsername = { lib, ... }: {
     wsl.defaultUser = lib.mkForce "different";

configuration.nix

@@ -26,11 +26,48 @@
       };
       nixosModules.default = self.nixosModules.wsl;
 
-      nixosConfigurations.mysystem = nixpkgs.lib.nixosSystem {
-        system = "x86_64-linux";
-        modules = [
-          ./configuration.nix
-        ];
+      nixosConfigurations = {
+        modern = nixpkgs.lib.nixosSystem {
+          system = "x86_64-linux";
+          modules = [
+            self.nixosModules.default
+            { wsl.enable = true; }
+          ];
+        };
+
+        legacy = nixpkgs.lib.nixosSystem {
+          system = "x86_64-linux";
+          modules = [
+            self.nixosModules.default
+            {
+              wsl.enable = true;
+              wsl.nativeSystemd = false;
+            }
+          ];
+        };
+
+        test = nixpkgs.lib.nixosSystem {
+          system = "x86_64-linux";
+          modules = [
+            self.nixosModules.default
+            ({ config, pkgs, ... }: {
+              wsl.enable = true;
+              wsl.nativeSystemd = false;
+
+              system.activationScripts.create-test-entrypoint.text =
+                let
+                  syschdemdProxy = pkgs.writeShellScript "syschdemd-proxy" ''
+                    shell=$(${pkgs.glibc.bin}/bin/getent passwd root | ${pkgs.coreutils}/bin/cut -d: -f7)
+                    exec $shell $@
+                  '';
+                in
+                ''
+                  mkdir -p /bin
+                  ln -sfn ${syschdemdProxy} /bin/syschdemd
+                '';
+            })
+          ];
+        };
       };
 
     } //