nixos-crostini: NixOS containers in ChromeOS

This repository provides a sample Nix configuration to build NixOS containers for Crostini (Linux on ChromeOS). The crostini.nix module adds support for:

• clipboard sharing with the container,
• handling of URIs, URLs, etc,
• file sharing,
• and X/Wayland support, so that the container can run GUI applications.

See this blog post for more details.

Quick start

1. Install Nix.
2. Run nix flake init -t github:aldur/nixos-crostini from a new directory (or simply clone this repository).
3. Edit the ./configuration.nix with your username; later on, pick the same when configuring Linux on ChromeOS.

Then:

# Build the container image and its metadata:
$ nix build
$ ls result
image.tar.xz  metadata.tar.xz

That's it! See this other blog post for a few ways on how to deploy the image on the Chromebook.

NixOS module

You can also integrate the crostini.nix module in your Nix configuration. If you are using flakes:

1. Add this flake as an input.
2. Add inputs.nixos-crostini.nixosModules.nixos-crostini to your modules.

Here is a very minimal example:

{
  # Here is the input.
  inputs.nixos-crostini.url = "github:aldur/nixos-crostini";

  # Optional:
  inputs.nixos-crostini.inputs.nixpkgs.follows = "nixpkgs";

  outputs = { self, nixpkgs, nixos-crostini }: {
    # Change to your hostname.
    nixosConfigurations.yourhostname = nixpkgs.lib.nixosSystem {
      modules = [
        ./configuration.nix

        # Here is where it gets added to the modules.
        nixos-crostini.nixosModules.default
      ];
    };

    # Change <system> to  "x86_64-linux", "aarch64-linux"
    # This will allow you to build the image.
    packages."<system>".lxc-image-and-metadata = nixos-crostini.packages."<system>".default;
  };
}

Modifications & Build Artifacts

This fork includes several specific modifications and improvements:

1. User Configuration: The default user is pre-configured as ertugrulerata in configuration.nix.
2. CI/CD Pipeline: A GitHub Actions workflow (.github/workflows/ci.yml) is included to automatically build the LXC image and metadata.
   • Artifacts: Every build produces image.tar.xz and metadata.tar.xz, which can be downloaded from the "Actions" tab in GitHub.
3. Flake Fixes: The crostini.nix module is explicitly included in the flake outputs to ensure critical files (like /etc/gshadow via common.nix) are generated correctly during the LXC build.
4. Baguette Exclusion: Specific "Baguette" related features have been excluded to keep the image minimal and focused on standard Crostini usage.

Downloading the Build

You do not need to build locally if you use the CI artifacts:

1. Go to the Actions tab of this repository.
2. Click on the latest successful workflow run.
3. Scroll down to Artifacts and download nixos-crostini-x86_64-linux.
4. Extract the zip file to get image.tar.xz and metadata.tar.xz.