vCenter HA (VCHA) may perform repeated failover operations every 5 to 10 minutes due to time synchronization issues.

Products

• VMware vCenter Server

Issue/Introduction

• vCenter HA may failover repeatedly every 5 to 10 minutes.
• "VCHA flapping" and "vCenter services restarting frequently"
• vCenter HA pair fails back and forth with pschealth exited unexpectedly messages similar to below in var/log/vmware/vmon/vmon.log:

  yyyy-mm-dd warning vmon Service pschealth exited. Exit code 1
  yyyy-mm-dd warning vmon Service pschealth exited unexpectedly. Crash count 0. Taking configured recovery action.

  
   
• In the /var/log/messages, you see entries similar to:

  yyyy-mm-dd su[33644]: pam_unix(su:session): session closed for user vpostgres
  yyyy-mm-dd ntpd[1244]: kernel reports TIME_ERROR: 0x41: Clock Unsynchronized
  yyyy-mm-dd ntpd[1244]: frequency error -119309 PPM exceeds tolerance 500 PPM
  yyyy-mm-dd systemd[1]: Time has been changed

Environment

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

Cause

This issue occurs when the ESXi host on which the active, passive and witness nodes reside are out of time sync. The Photon OS for vCenter Server will sync with the time on the ESXi host periodically, and if NTP is not configured correctly, it can cause the time inside the Guest OS to drift. If the time drifts too much, this can trigger a failover between the Active/Passive VCHA appliances.

Resolution

1. Verify NTP configuration on all three ESXi hosts hosting the Active, Passive, and Witness nodes.
2. Ensure the NTP service is running on each host.
3. Confirm all hosts are pointed to a consistent, reliable NTP server.
4. Verify the vCenter Server Appliance (VCSA) itself is synchronized via the VAMI (port 5480).

Additional Information

For more information on ESX/ESXi timekeeping best practices, refer to ESX and ESXi host time keeping best practices