Operating System Image Management

PCD Kubernetes allows the flexibility to use your own Operating System (OS) to use with your Kubernetes clusters. It requires Cluster API compliant Operating System Images uploaded into Image Library specific to Kubernetes version you want to deploy. The ability to bring your own OS to PCD gives you more control over dependencies in your environment and ensures compatibility with your existing applications. The OS you bring can be commercial or an open source distribution.

Building OS image

You can use OpenstackImageBuilder based on the KubernetesImageBuilder to create your own OS images on your machine. PCD currently support only Ubuntu 22.04 as the OS for worker nodes and qcow2 as the image format.

Pre-requisites: qemu and libvirt running

Steps:

Bash

git clone https://github.com/kubernetes-sigs/image-builder.git 
make deps-qemu 
PACKER_LOG=1 make build-qemu-ubuntu-2204

The OS and its supported versions are defined in images/capi/packer/qemu/. Any modifications to the build-qemu command for building different OS versions can also be found there.

By default make will use the latest kube version. To build specific kube version. Update the kube version in the following file and run the make again.

Bash

# cat image-builder/images/capi/packer/config/kubernetes.json
{
"crictl_arch": "amd64",
"crictl_sha256": "https://github.com/kubernetes-sigs/cri-tools/releases/download/v%7B%7Buser crictl_version}}/crictl-v{{user crictl_version}}-linux-{{user crictl_arch}}.tar.gz.sha256",
"crictl_source_type": "pkg",
"crictl_url": "https://github.com/kubernetes-sigs/cri-tools/releases/download/v%7B%7Buser crictl_version}}/crictl-v{{user crictl_version}}-linux-{{user crictl_arch}}.tar.gz",
"crictl_version": "1.29.0",
"kubeadm_template": "etc/kubeadm.yml",
"kubernetes_apiserver_port": "6443",
"kubernetes_container_registry": "GitHub - kubernetes/registry.k8s.io: This project is the repo for registry.k8s.io, the production OCI registry service for Kubernetes' container image artifacts ",
"kubernetes_deb_gpg_key": "https://pkgs.k8s.io/core:/stable:/{{ user kubernetes_series }}/deb/Release.key",
"kubernetes_deb_repo": "https://pkgs.k8s.io/core:/stable:/{{ user kubernetes_series }}/deb/",
"kubernetes_deb_version": "v1.29.11-1.1",
"kubernetes_goarch": "amd64",
"kubernetes_http_source": "https://dl.k8s.io/release",
"kubernetes_load_additional_imgs": "false",
"kubernetes_rpm_gpg_check": "True",
"kubernetes_rpm_gpg_key": "https://pkgs.k8s.io/core:/stable:/{{ user kubernetes_series }}/rpm/repodata/repomd.xml.key",
"kubernetes_rpm_repo": "https://pkgs.k8s.io/core:/stable:/{{ user kubernetes_series }}/rpm/",
"kubernetes_rpm_repo_arch": "x86_64",
"kubernetes_rpm_version": "v1.29.11",
"kubernetes_semver": "v1.29.11",
"kubernetes_series": "v1.29",
"kubernetes_source_type": "pkg",
"systemd_prefix": "/usr/lib/systemd",
"sysusr_prefix": "/usr",
"sysusrlocal_prefix": "/usr/local"
}

Uploading OS Images to PCD Image Library

You can user the PCD UI or OpenStack CLI to upload an image to the Image Library & Images in PCD. Please follow the instructions in the Image Library & Images to import the generated qcow2 image into PCD.

Adding required Properties to OS Images

PCD required following properties to be present on the Image to be used for creating Kubernetes Node VMs in PCD. These are required to identify the image build for a specific Kubernetes version.

Property Key	Property Value
k8s_version	Kubernetes version in formation major.minor version. Eg 1.30 or 1.31

You can add the image property after the image is imported to PCD via the PCD UI. Go to the Virtualized Cluster > Images Page and select the image to add properties. Click on Edit Properties to add the image. Once the Properties are added, the image properties should appear as below in PCD.