vSphere HA Configuration stuck in "Election" state for a new host, fails with "Operation Timed out" in vCenter Server

Products

• VMware vSphere ESX 8.x

Issue/Introduction

A host was newly added to a cluster or a new cluster was deployed. Following logs can be seen in /var/log/fdm.log file of the affected host:

YYYY-MM-DDTHH:MM:SS.154Z In(166) Fdm[2152225]: [Originator@6876 sub=Cluster opID=clusterElection.cpp:1570-1ffabd8a] Connecting to master host-xxxxxxVMware vSphere ESXi
 @ x.x.x.x:8182
...
YYYY-MM-DDTHH:MM:SS.165Z Er(163) Fdm[2152225]: [Originator@6876 sub=Cluster opID=clusterElection.cpp:1570-1ffabd8a] Couldn't connect to master N7Vmacore16Tim
eoutExceptionE(Operation timed out)
...
YYYY-MM-DDTHH:MM:SS.165Z Db(167) Fdm[2152225]: [Originator@6876 sub=Cluster opID=clusterElection.cpp:1570-1ffabd8a] IP x.x.x.x marked bad for reason Unreachable IP

Environment

VMware vSphere ESXi

Cause

Bidirectional communication over TCP & UDP port 8182 is not allowed between the hosts in the cluster where HA is being enabled.

Resolution

Bidirectional communication over TCP & UDP port 8182 is required for vSphere High Availability. Please ensure this port is allowed between the hosts in the cluster where HA is being enabled. For more information refer to https://ports.broadcom.com/home/vSphere.

For other potential failure reasons, please refer to this KB article - 334269.