osbuild

A build system for operating system images, working towards an image build pipeline that's more comprehensible, reproducible, and extendable.

Pipelines

The build process for an image is described by a pipeline. Each stage in a pipeline is a program that, given some configuration, modifies a file system tree. Pipelines are defined as JSON files like this one:

{
  "name": "Example Image",
  "pipeline": [
    {
      "name": "io.weldr.dnf",
      "options": {
        "packages": [ "@core", "httpd" ]
      }
    },
    {
      "name": "io.weldr.systemd",
      "options": {
        "enabled_services": [ "httpd" ]
      }
    },
    {
      "name": "io.weldr.qcow2",
      "options": {
        "target": "output.qcow2"
      }
    }
  ]
}

osbuild runs each of the stages in turn, isolating them from the host and from each other, with the exception that the first stage may be given an input directory, the last stage an output directory and all stages of a given pipeline are given the same filesystem tree to operate on.

Each stage is passed the (appended) options object as JSON over stdin.

The above pipeline has no input and produces a qcow2 image.

Running

osbuild [--input DIRECTORY] [--output DIRECTORY] PIPELINE

Runs PIPELINE. If --input is given, the directory is available read-only in the first stage. If --output is given it, it must be empty and is avialble read-write in the final stage.