naext: Nix Appliance Extension Tools

Extending Appliance Images.

NixOS allows for building Appliance Images. Since Appliance Images are immutable they typically contain everything necessary to make use of such an image.

Problem

Appliances are usually built generically. To be useful an appliance is augmented with specifics (think of configuration, programs) for a certain use case.

Offered Solution

This project offers solutions to extend immutable appliances in a lightweight manner leveraging technologies provided by systemd and the kernel.

naext Module

Allows for building extension images (sysext, confext).

Example

Create a confext image that provides the file /etc/test containing Hello.

naext = {
  seed = "12345678-1234-1234-1234-123456789123";
  extensions = {
    "hello" = {
      extensionType = "confext";
      imageFormat = "raw";
      files = {
        "/etc/test".source = pkgs.writeText "example" ''Hello'';
      };
    };
  };
};

Tour

Check out:

• Building an Image with nix-build ./examples/basic.nix
• Basic Integration Test with nix-build ./examples/basic.nix
• Integration Test with verity protected extension image with nix-build ./examples/basic.nix