Supervisor control plane VM is unable to validate the vCenter certificate due to duplicate FQDN entries in DNS

Products

• VMware vSphere Kubernetes Service

Issue/Introduction

• Supervisor cluster is down due to a certificate validation failure between the Supervisor Control Plane VM and vCenter Server
• Error message: 
  Configuration error The control plane VM <control_plane_vm> was unable to validate the vCenter <vCenter_FQDN> certificate. The vCenter server certificate is invalid.
• The vCenter Server certificate has been validated to be valid 
• Doing an nslookup from different supervisor control plane VMs on the vCenter FQDN is returning different IPs 

Environment

• VMware Kubernetes Service (VKS)
• VMware vCenter Server 8.x 

Cause

• If different IPs are returned via nslookup on the vCenter Server FQDN then a duplicate entry exists in DNS containing the same FQDN with different IPs
• The supervisor control plane VM(s) in error state are unable to validate the certificate from the incorrect IP

Resolution

Remove the duplicate/incorrect DNS entry