Unable to Upgrade VKS Workload Cluster to version 1.33 from TMC SaaS

Products

• Tanzu Kubernetes Runtime

Issue/Introduction

During the attempt to upgrade a VKS Workload Cluster to version 1.33 from TMC SaaS, the following error is observed:

API Error: Failed to upgrade cluster: (target=xxxxxx): admission webhook "default.validating.tanzukubernetescluster.run.tanzu.vmware.com" denied the request: Kubernetes release with version v1.33 and above is only supported with Cluster API. (invalid argument)

This occurs because the target cluster is still managed as a legacy TKC (Tanzu Kubernetes Cluster) object, which does not support Kubernetes versions 1.33 and above.

Cause

The workload cluster is managed as a TKC instead of a ClusterClass–based (VKS) cluster.

TKC clusters are deprecated and not compatible with Kubernetes versions 1.33 and newer. The admission webhook prevents the upgrade since only Cluster API–based clusters can support these newer versions.

Resolution

Retire the existing TKC cluster following the official Broadcom documentation:

• Retire TKG Clusters

Once the TKC cluster has been retired, proceed with the upgrade through TMC.

After the retirement process, the workload cluster becomes a Cluster API–managed VKS cluster, allowing successful upgrade to version 1.33 and beyond.