Community images
Azimuth requires a number of specialised images to be available on the target cloud for Cluster-as-a-Service appliances and Kubernetes clusters.
Images for Kubernetes and CaaS appliances, with the exception of Slurm, are built using Packer from the definitions in the azimuth-images repository. For Kubernetes, we make use of the recipes from the upstream Cluster API image-builder.
Each release of azimuth-images has an associated manifest that describes the images in the release and where to download them from, along with some additional metadata. The Azimuth deployment playbooks are able to consume these manifests.
Images for the Slurm cluster appliance are built using Packer from definitions in the slurm-image-builder respository, with builds uploaded here.
azimuth-ops is able to download, convert (if required) and then create
Glance images on the target cloud from these sources.
Images are uploaded as
community images
meaning they are accessible by all projects in the target cloud, but not included by default
when listing images in Horizon, the OpenStack CLI or the OpenStack API.
By default, azimuth-ops uploads the set of images that are needed to support Azimuth's
functionality and auto-wires them into the correct places for the K3S node, the HA Kubernetes
cluster, the default Kubernetes templates and the default Cluster-as-a-Service appliances.
Image properties
Properties can be set on the uploaded images, if required. The properties are given as
strings of the form key=value in the following variable:
community_images_custom_properties:
- 'prop1=value1'
- 'prop2=value2'
Image conversion
Images can be converted from a "source" format to a "target" format for the target cloud. The
majority of images available for download are in qcow2 format, and this is the format in
which images built from azimuth-images are distributed. However your cloud may require
images to be uploaded in a different format, e.g. raw or vmdk.
To specify the target format for your cloud, just set the following (the default is qcow2):
When this differs from the source format for an image, azimuth-ops will convert the image
using qemu-img convert before uploading it to the
target cloud.
Disabling community images
It is possible to prevent azimuth-ops from uploading any images, even the default ones,
by setting the following:
Warning
If community images are disabled you will need to ensure suitable images are uploaded via another mechanism, and the correct variables populated with the image IDs in your Azimuth configuration. See the azimuth-ops roles for more details.
Custom images
If you want to upload custom images as part of your Azimuth installation, for example to support
a custom Cluster-as-a-Service appliance or for older Kubernetes versions, you can use the
community_images_extra variable:
community_images_extra:
# Key, used to refer to the image ID
debian_11:
# The name of the image to create on the target cloud
name: debian-11-generic-amd64-20220711-1073
# The URL of the source image
source_url: https://cloud.debian.org/images/cloud/bullseye/20220711-1073/debian-11-generic-amd64-20220711-1073.qcow2
# The disk format of the source image
source_disk_format: qcow2
# The container format of the source image
container_format: bare
The ID of this image can then be referred to elsewhere in your Azimuth configuration using:
my_custom_caas_appliance_image: "{{ community_images_image_ids.debian_11 }}"
Warning
It is assumed that the name in a community image specification refers to a unique image.
azimuth-ops will only download, convert and upload images to the target cloud for names
that do not already exist.
For this reason, it is recommended to include a timestamp or build reference in the image name in order to identify different images that serve the same purpose (e.g. different builds of the same pipeline).
Created: April 9, 2024