After vCenter 8.0 U3i Patch: “Unable to find a master vSphere HA agent in cluster”

Products

• VMware vCenter Server

Issue/Introduction

• After patching vCenter Server from 8.0 Update 3h to 8.0 Update 3i, clusters may report the following error:
  
  "vCenter Server is unable to find a master vSphere HA agent in cluster."
  
  
• In this condition, one or more hosts may fail to rejoin the HA cluster and report errors similar to:
  
  "The host is reporting errors in its attempts to provide vSphere HA support."
  
  
• Additionally, under Cluster > Updates > Image, the following error may be displayed:
  
  "No healthy upstream."



• Verify the condition in the VUM logs.
  
  Review the logs located at:

  /var/log/vmware/vmware-updatemgr

  The issue can be identified when vsphere-fdm appears both as a standalone component and as part of the HA solution, for example:

  --> "components": {
--> "VMware-VM-Tools": "13.0.5-0.24916190",
--> "vsphere-fdm": "8.0.3-24853646"
--> },
--> "solutions": {
--> "com.vmware.vsphere-ha": {
--> "components": [
--> {
--> "component": "vsphere-fdm"
--> }
--> ],
--> "version": "8.0.3-25197330"
--> }
--> }

  In this condition, vsphere-fdm is defined both as a component and within the HA solution, creating a duplicate HA component definition.

Environment

VMware vCenter 8.x

Cause

This issue may occur after the vCenter upgrade due to an inconsistency in the HA component definitions within the vSphere Lifecycle Manager image. In certain scenarios, the upgrade process may leave duplicate HA component references, resulting in a conflict when resolving the HA configuration for the cluster.

Resolution

 

1. Verify the status of the vCenter services and confirm whether the vmware-updatemgr service is running.

   Check service status:

   vmon-cli --status

2. If the vmware-updatemgr service is stopped, start it:

   vmon-cli -i updatemgr

3. In the vSphere Client, navigate to Cluster > Updates > Image and review the Desired Image configuration.
   
   
4. If the vsphere-fdm component appears listed as a user-added component, remove it from the image configuration.
   
   
5. Save the changes and apply the updated image configuration to the cluster.
   
   
6. After removing the duplicate vsphere-fdm component, reconfigure vSphere HA if necessary so the cluster can elect a master HA agent.