ESXi reports the HA error: HA may not be able to restart VMs if a host failure occurs

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• For an ESXi host, you see an error message similar to:
  
  vSphere HA agent on host km-pdp057 in cluster cannot reach some of the management network addresses of other hosts and thus HA may not able to restart VMs if a host failure occurs
   
• The Summary tab of the host reports this error:
  
  The vSphere HA agent on this host cannot reach some of the management network addresses of other hosts, and HA may not be able to restart VMs if a host failure occurs: FQDN:IP
   
• Virtual machines do not failover to other hosts in the cluster when High Availability (HA) is triggered.

Environment

VMware vCenter Server 6.x
VMware vCenter Server 7.x
VMware vCenter Server 8.x

Cause

This issue occurs when a host experiencing an HA event cannot ping or reach the Management Network IP address of other hosts in the cluster, possibly due to firewall rules, an incorrect Management Network IP, use of IPv6, or other network connectivity issues.

Resolution

To troubleshoot issues related to Management Network connection between hosts, see:

• Troubleshooting VMware High Availability (HA) issues in VMware vCenter Server
• Restarting the Management agents in ESXi

In addition, ensure that you are able to ping the Management Network of each host from the host that experienced the HA event. In the event that a host has permanently failed, remove that host from the affected cluster and reconfigure HA.

Additional Information