torcx - a boot-time addon manager

torcx (pronounced "torks") is a boot-time manager for system-wide ephemeral customization of Linux systems. It has been built specifically to work with an immutable OS such as Container Linux by CoreOS.

torcx focuses on:

• providing a way for users to add additional binaries and services, even if not shipped in the base image
• allowing users to pin specific software versions, in a seamless and system-wide way
• supplying human- and machine-friendly interfaces to work with images and profiles

Getting started

This project provides a very lightweight add-ons manager for otherwise immutable distributions. It applies collections of addon packages (named, respectively, "profiles" and "images") at boot-time, extracting them on the side of the base OS.

Profiles are simple JSON files, usually stored under /etc/torcx/profiles/ with a .json extension, containing a set of image-references:

{
  "kind": "profile-manifest-v1",
  "value": {
    "images": [
      {
        "name": "foo-addon",
        "reference": "0.1",
        "remote": "com.example.foo"
      }
    ]
  }
}

Image archives are looked up in several search paths, called "stores":

1. Vendor store: usually on a read-only partition, it contains addons distributed together with the OS image
2. User store: usually on a writable partition, it contains images provided by the user
3. Runtime store: additional search path specified at runtime

At boot-time, torcx unpacks and propagates the addons defined in the active profile, specified in /etc/torcx/next-profile. Once done, torcx seals the system into its new state and records its own metadata under /run/metadata/torcx.

License

torcx is released under the Apache 2.0 license. See the LICENSE file for all details.