vSAN Cluster shutdown preparation fails with an error: "Please enable NTP service across the hosts and vCenter Server or synchronize the time settings manually".

Products

• VMware vSAN

Issue/Introduction

Symptoms:

When attempting to shut down a vSAN cluster for maintenance, the following issue may occur:

• The reboot_helper.py prepare script fails with the error: Please enable NTP service across the hosts and vCenter Server, or synchronize the time settings manually
  
  
• This issue can occur when vCenter Server is powered off and the shutdown script is executed manually on an ESXi host: python /usr/lib/vmware/vsan/bin/reboot_helper.py prepare

Environment

VMware vSAN 8.x

Cause

One or more ESXi hosts in the vSAN cluster exhibit a time drift greater than 10 seconds compared to other hosts. This time skew causes the script to fail, as accurate time synchronization is required for a graceful cluster shutdown.

Resolution

Accurate time synchronization is critical for vSAN operations. Time drift across hosts can negatively impact the cluster shutdown process.

1. Verify that the NTP service is running on all ESXi hosts: #/etc/init.d/ntpd status

2. If necessary, restart the NTP service on affected hosts: #/etc/init.d/ntpd restart

3. Confirm time consistency across all hosts by running: #watch date compare the time output across all cluster hosts.

4. If significant time drift persists despite NTP being active, manually correct the time on the affected host(s).
   Once the time is synchronized across all hosts, rerun the script: python /usr/lib/vmware/vsan/bin/reboot_helper.py prepare
   The script should then complete successfully, allowing the cluster to shut down gracefully.