diskimage-builder can create many different types of targets
composed of many different elements. For any release, the project
considers the elements tested by the OpenDev gate
continuous-integration jobs as stable.
Practically, this means a change can not commit unless it has successfully built the elements described below under test.
The build-host is the platform used to create images. Unfortunately
there is no concise answer as to the support status of all possible
diskimage-builder has a complex relationship with
the build-host depending on which target elements are being built.
Image-based elements take an upstream
.qcow2 image, extract and
customise it. Since
diskimage-builder chroots into an
already-complete environment, these elements generally work on any
build-host, but there are complexities; for example some images ship
an XFS-filesystem with options that some stable-distribution
build-hosts can not read (and hence the build-host can not mount and
extract the image).
As another example, the
-minimal elements run tools such as
apt on the build-host to create an initial
chroot environment. Thus some combinations will not work; for
fedora-minimal for the latest versions may require a RPM
that is not packaged on current stable versions of Ubuntu. Some
versions of Ubuntu ship a
debootstrap that has bugs preventing
building other distributions, etc.
containerfile elements use
podman to extract a
container-image and then customise that. Distributions vary in their
podman version and various bugs related to this.
The images used by the OpenDev’s Zuul system
are built by Nodepool. Thus
the simplest way to have the most supported build-host environment is
diskimage-buidler installed in the nodepool-builder
You can run
disk-image-create directly from this container, e.g.
docker run --rm --privileged --network host \ --env DIB_SHOW_IMAGE_USAGE=1 \ --env TMPDIR=/opt/dib_tmp \ -v nested_var_lib_containers:/var/lib/containers \ -v /var/run/dib_output:/var/run/dib_output \ -v /opt/dib_tmp:/opt/dib_tmp \ zuul/nodepool-builder disk-image-create -x -t qcow2 \ --no-tmpfs \ -o /var/run/dib_output/image -n <element(s)>
The platform this container image is built upon is by extension the most-supported build host. Inspecting the Dockerfile is a good way to start building customised build-host environments. This is currently based on Debian Bullsye.
Other distributions are not tested as build-hosts in the
Testing and Targets¶
The stable targets are those that are tested; as noted no change can commit which would break this testing.
There are two main testing paths:
end-to-end tests build an image, import it to an OpenStack environment, boot it and confirm basic operation. These tests use the
nodepool-buildercontainer environment to build the image to be tested.
functional tests build a complete output image. They do not perform boot tests. These tests run on Debian Bullseye.
The canonical list of tests and the elements they build for any releae is kept in .zuul.yaml/jobs.yaml. If this document differs to the defined tests, the Zuul configuration is correct.
As of Feburary 2022, the default end-to-end testing covers the following elements on x86-64
centos-minimal: CentOS 7, 8-stream and 9-stream
fedora-containerfile: the latest Fedora.
ubuntu-minimal: Ubuntu Xenial, Bionic and Focal
opensuse-minimal: Leap 15.3 and Tumbleweed (non-voting)
rocky-container: Rocky Linux 8
We run functional (build-only) tests on the following elements and versions:
containerfile: Ubuntu Focal
centos: (image-based build) 8-stream and 9-stream
fedora: (image-based build) latest
ubuntu: Bionic and Focal
For ARM64, we also run functional tests on
ubuntu-minimal: Bionic and Focal
centos-minimal: 8-stream and 9-stream
For additional details, see the
README file of the relevant
diskimage-builder is used in a range of other projects that do
their own testing, separate to the
diskimage-buidler CI gate
testing. These have different combinations of host/target elements
they keep stable. Updates to this document are welcome.