Question About Kubernetes Version Upgrade in Apache CloudStack

[marcoodamo]

Hello!

I hope you're doing well!

I'm trying to understand how the Kubernetes version upgrade process works when running on Apache CloudStack. My question is more about what happens "under the hood": Does the upgrade take place at the hypervisor level? Does it involve changes to the operating system of the VMs? How is compatibility between Kubernetes versions and the underlying infrastructure managed in this context?

If you could share some insights or point me to relevant documentation, I would greatly appreciate it!

Thank you in advance for your time.

[Pearl1594]

Hi,
Kubernetes upgrade just upgrades the k8s version. Just to give a high level overview of the steps:

1. First attaches the K8s ISO of the version of k8s that you want to upgrade to, to the respective nodes - control and worker node(s)
2. Drains each of the node - starting with the control node
3. Deploys the cloudstack-kubernetes-provider
4. Then runs the upgrade-kubernetes.sh script, which:
   a. mounts the attached iso on the the respective node
   b. imports the images (docker) required for the new k8s version
   c. runs the kubeadm upgrade command based on the node type
   d. copies the latest binaries - kubectl, kubelet from the ISO and restarts the services
   e. On the control node, applies the latest network and dashboard config
5. detaches the ISO from all of the cluster nodes

[marcoodamo]

Hi,

Thank you,

This upgrade is only between MINOR versions or can i upgrade MAJOR versions too?

Best Regards,
Marco Damo.

[weizhouapache]

Hi,

Thank you,

This upgrade is only between MINOR versions or can i upgrade MAJOR versions too?

Best Regards,
Marco Damo.

@marcoodamo
You can upgrade to the next MAJOR version.
For example, upgrade 1.27.x to 1.28.x

1.27.x to 1.29.x upgrade is unsupported.