DRS Fault "drs.migration.error.vmAntiAffinityPolicy" reported for VKS Worker Nodes

Products

• VMware vSphere Kubernetes Service

Issue/Introduction

The vSphere Client reports persistent DRS migration faults for VKS guest cluster nodes during normal operations.

Symptoms:

• Navigating to Cluster > Monitor > vSphere DRS > Faults displays alerts for Worker Node or Control Plane VMs as shown below 
  
• The error message is categorized as "drs.migration.error.vmAntiAffinityPolicy" and specifies the message "No host is compatible with the virtual machine".

Environment

VMware vSphere 7.x / 8.x
VMware vSphere Kubernetes Service

Cause

The vSphere Kubernetes Service (VKS) automatically generates implicit Anti-Affinity rules for nodes within the same nodepool.
This is intended to distribute Kubernetes nodes across as many physical ESXi hosts as possible to minimize the impact of a single host failure.

In environments where the number of nodes in a nodepool is greater than the available ESXi host count, DRS is not able to migrate the VM for load balancing because the other hosts already have a node from the same nodepool. 

Resolution

This behavior is expected and by design. No manual intervention is required to maintain the health of the Kubernetes cluster.
These faults are purely informational and indicate that the nodepool's high-availability placement requirements cannot be satisfied by the existing hosts in the cluster.

These faults can be ignored as they do not impact VM performance or DRS functionality for non-VKS workloads.