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.

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:

• Build an Appliance for OpenStack with discovery mechanism (pull) with nix build .#packages.x86_64-linux.openstackExampleAppliance
• Build a Hedgedoc Appliance that expects it's extension image to be pushed with nix build .#packages.x86_64-linux.hedgedocExampleAppliance
• Basic Integration Test