Setting up Fault Tolerance(FT) for VMs on the vCenter Server fails with error "Failed to power on FT secondary VM"

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

• Setting up fault tolerance fails with error on the UI suggesting a failure in powering the secondary VM on :
  

  vCenter cannot start the Fault Tolerance secondary VM for VM_NAME (primary) on host PRIMARY_ESXI_HOST in cluster Cluster01 in Datacenter . 
  	Reason: VmFailedStartingSecondaryEvent.FailureReason.Failed to power on FT secondary VM..label  
  vCenter disabled Fault Tolerance on VM VM_NAME (primary) on host PRIMARY_ESXI_HOST in cluster Cluster## in Datacenter because the Secondary VM could not be powered On.  
  Fault Tolerance VM VM_NAME (primary) syncing to secondary on SECONDARY_ESXI_HOST with encryption
  Starting Fault Tolerance secondary VM for VM_NAME (primary) on host PRIMARY_ESXI_HOST in cluster VM-Cluster in Datacenter

• The secondary VM fails to power on
  
  

Environment

VMware vCenter Server
VMware vSphere ESXi

Cause

Issues with networking such as misconfigured uplinks or vSwitch used for Fault Tolerance can cause the error to be shown. 

Resolution

Identify if the issue is with communication between the secondary and primary host :

• Check if vmkpings are failing over the vmk on which the Fault Tolerance network is expected to communicate from the secondary ESXi host:
  vmkping -I vmk# <ip address of primary esxi host>


• Check if there are any connections established between the primary and secondary host on port 8300:
  esxcli network ip connection list | grep 8300

To resolve the network issue :

• Verify that the networks have been configured correctly for Fault Tolerance 
  • Best Practices for Fault Tolerance
  • Fault Tolerance Checklist

• On the vSwitch for Fault tolerance on each of the involved hosts , check if the Physical Adapters are identically configured.
  • To Check vSwitch go to Host > Configure > Networking > Virtual Switches > Fault Tolerance Switch and click on Manage Physical Adapters .

• If the network issue persists, please reach out to Broadcom Support. 

Additional Information

Port requirements for VMware vSphere ESXi