This document provides a conceptual overview about the steps of creating an image with KIWI NG. It also explains the terminology regarding the concept and process when building system images with KIWI NG 10.0.21.

Conceptual Overview

A system image (usually called “image”), is a complete installation of a Linux system within a file. The image represents an operation system and, optionally, contains the “final” configuration.

KIWI NG creates images in a two step process:

  1. The first step, the prepare operation, generates a so-called unpacked image tree (directory) using the information provided in the image description.

  2. The second step, the create operation, creates the packed image or image in the specified format based on the unpacked image and the information provided in the configuration file.

The image creation process with KIWI NG is automated and does not require any user interaction. The information required for the image creation process is provided by the image description.



An appliance is a ready to use image of an operating system including a pre-configured application for a specific use case. The appliance is provided as an image file and needs to be deployed to, or activated in the target system or service.


The result of a KIWI NG build process.

Image Description

Specification to define an appliance. The image description is a collection of human readable files in a directory. At least one XML file config.xml or .kiwi is required. In addition there may be as well other files like scripts or configuration data. These can be used to customize certain parts either of the KIWI NG build process or of the initial start-up behavior of the image.

Overlay Files

A directory structure with files and subdirectories stored as part of the Image Description. This directory structure is packaged as a file root.tar.gz or stored inside a directory named root. Additional overlay directories for selected profiles are supported too and are taken into account if the directory name matches the name of the profile. The content of each of the directory structures is copied on top of the existing file system (overlayed) of the appliance root. This also includes permissions and attributes as a supplement.


An OS appliance builder.

Virtualization Technology

Software simulated computer hardware. A virtual machine acts like a real computer, but is separated from the physical hardware. Within this documentation the QEMU virtualization system is used. Another popular alternative is Virtualbox.

System Requirements

To use and run KIWI NG, you need:

  • A recent Linux distribution, see Build Host Constraints for details.

  • Enough free disk space to build and store the image. We recommend a minimum of 15GB.

  • Python version 3.5 or higher

  • Git (package git) to clone a repository.

  • Any virtualization technology to start the image. We recommend QEMU.