vSphere HA initialization failing on cluster

Products

• VMware vCenter Server

Issue/Introduction

When attempting to turn on vSphere HA for a cluster and the tasks "Configuring vSphere HA on the cluster" and "Remediate HA" fail with errors like "Cannot complete the vSphere HA configuration agent on the host 'Applying HA VIBs on the cluster encountered a failure.'" and "A general system error occurred: Installing HA components failed on the cluster", respectively. 

Environment

vSphere 7

vSphere 8

Cause

Ports like 9084 and 9087 that required for vSphere Lifecycle Manager communcations are blocked from the ESXi Host Management IP address to the vCenter Server Management IP address.

Resolution

• Check the above ports with these commands:

nc -zv <vcenter_fqdn> 9084

nc -zv <vcenter_fqdn> 90847

• If they are blocked, then work with your network team to make sure those ports are open from the ESXi Host Management IP address to the vCenter Server Management IP address.

Additional Information

vSphere Port Webpage

Port requirements for VMware vSphere ESXi