Build KIS Image (Kernel, Initrd, System)

Abstract

This page explains how to build an image that consists out of three components. The kernel an initrd and an optional root filesystem image. In KIWI NG terminology this is called KIS.

A KIS image is a collection of image components that are not associated with a dedicated use case. This means from a KIWI NG perspective we don’t know in which environment these components are later used. The predecessor of this image type was called pxe under the assumption that the components will be used in a pxe boot environment. However this assumption is not neccessarily true and the image components are used in a different way. Because there are so many possible deployment strategies for a kernel plus initrd and optional system root filesystem, KIWI NG provides this as generic KIS type that is generically usable.

The former pxe image type will continue to exist but is expected to be used only in combination with the legacy netboot infrastructure as described in Build PXE Root File System Image for the legacy netboot infrastructure.

To add a KIS build to your appliance, create a type element with image set to kis in your config.xml as shown below:

<preferences>
    <type image="kis"/>
</preferences>

With this image type setup KIWI NG will just build a kernel and initrd not associated to any system root file system. Usually such an image is only useful with some custom dracut extensions as part of the image description.

The following attributes of the type element are often used when building KIS images:

• filesystem: Specifies the root filesystem and triggers the build of an additional filesystem image of that filesystem. The generated kernel command line options file (append file) will then also include a root= parameter that references this filesystem image UUID. If the information from the append file should be used or not is optional.

• kernelcmdline: Specifies kernel command line options that will be part of the generated kernel command line options file (append file). By default the append file contains no information or the reference to the root UUID if the filesystem attribute is used.

All other attributes of the type element that applies to an optional root filesystem image will be effective in the system image of a KIS image as well.

With the appropriate settings present in config.xml KIWI NG can now build the image:

$ sudo kiwi-ng --type kis system build \
    --description kiwi/build-tests/x86/tumbleweed/test-image-pxe \
    --set-repo http://download.opensuse.org/tumbleweed/repo/oss \
    --target-dir /tmp/myimage

The resulting image components are saved in the folder /tmp/myimage. Outside of a deployment infrastructure the example KIS image can be tested with QEMU as follows:

$ sudo qemu
    -kernel /tmp/myimage/*.kernel \
    -initrd /tmp/myimage/*.initrd \
    -append $(cat /tmp/myimage/*.append) \
    -hda /tmp/myimage/kiwi-test-image-pxe.*-1.15.3 \
    -serial stdio

Note

For testing the components of a KIS image a deployment infrastructure and also a deployment process is usually needed. One example of a deployment infrastructure using PXE is provided by KIWI NG with the netboot infrastructure. However that netboot infrastructure is no longer developed and only kept for compatibiliy reasons. For details see Build PXE Root File System Image for the legacy netboot infrastructure