Alarm "Cannot find vSphere HA master agent" was triggered after newly deployed HA cluster

Products

• VMware vCenter Server

Issue/Introduction

• Alarm "vSphere HA Master Agent not found" was triggered on the HA cluster summary tab in vSphere client after newly deployed HA cluster
  
• The below error are also seen on the HA cluster summary tab in vSphere client
  
  
  • vCenter Server is unable to find a master vSphere HA agent in cluster <CLUSTER_NAME> in <DATACENTER_NAME>

Environment

VMware vSphere ESXi 8.x

Cause

• This issue is caused by HA configuration failing on all hosts within the cluster, preventing master election.

• A possible reason HA cannot be configured on a host is that a datastore is not configured or mounted on that host.
  For more information on this, see vSphere HA configuration fails on newly deployed ESXi host

Resolution

To resolve this issue:

1. Create and mount a datastore on the affected host.
2. Disabling and enabling vSphere HA 

The process of Disabling and enabling vSphere HA is described in Disabling and enabling VMware vSphere High Availability (vSphere HA).

Additional Information

• vSphere HA configuration fails on newly deployed ESXi host
  
  
• Disabling and enabling VMware vSphere High Availability (vSphere HA)