Host has no isolation addresses defined as required by vSphere HA

Products

• VMware vCenter Server

Issue/Introduction

^{An Alarm "Host has no isolation addresses defined as required by vSphere HA" will be triggered on Esxi.}

Environment

^{VMware vCenter Server 5.x}

^{VMware vCenter Server 6.x}

^{VMware vCenter Server 7.x}

^{VMware vCenter Server 8.x}

Cause

^{vSphere HA always checks if an isolation address is specified, which could be either the default gateway of the management network or the isolation address specified through advanced settings ie. das.isolationaddress.}

vSphere HA Advance Parameter value is false

das.isolationaddress   false

Resolution

Select the Cluster where the Hosts are reporting alert "Host has no isolation addresses defined as required by vSphere HA"

1. Navigate to Configure Tab and Select vSphere HA

1. • Click Edit setting vSphere HA
     
2. Navigate to Advanced Options
   
3. Change the Value of Parameter from "false" to "true"
   

   das.isolationaddress    true 

   
   
4. Go to vSphere UI and select the affected ESXi Hosts and Reconfigure vSphere HA.

Note: If the Issue remains' the same make sure to verify if the Host Network Configuration "IP, Subnet Mask, Default Gateway and DNS" are in place and reconfigure the HA on the Hosts
Please refer to the URL: https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.virtualsan.doc/GUID-8105EE33-2346-4299-9540-41C488A2A8D0.html and configure Default gateway.