The NTP server sequence appear incorrectly in the vCenter Server Management Interface (VAMI).

Products

• VMware vCenter Server

Issue/Introduction

In vCenter Server 8.x, the NTP server list shown in the VAMI (Port 5480) may not always match the order or the changes made through the UI. This can happen even when following the standard procedure to -  Add or Replace NTP Servers in the vCenter Server Configuration

Environment

VMware vCenter Server 8.x

Cause

This issue is caused by configuration drift where a different or legacy sequence persists directly within the /etc/ntp.conf file. The vCenter Server management components retrieve and display information based on the active state of this file. If manual modifications or legacy entries exist, the VAMI may fail to overwrite the sequence via the UI, resulting in a display mismatch.

Verification of this configuration drift requires a direct comparative analysis between the intended state (as defined in the VAMI) and the actual running state (as defined in the /etc/ntp.conf file).

Example of Configuration Drift (NTP Sequence Scenario)
To illustrate configuration drift, the following masked example demonstrates the divergence between the VAMI and the appliance's core configuration.

Expected order (VAMI UI Configuration):

The management interface dictates that time synchronization should occur using four specific servers in a defined order.

NTP Server 1: 10.237.X.X

NTP Server 2: 10.240.X.X

NTP Server 3: 10.221.X.X

NTP Server 4: 10.224.X.X

Actual State (Output of cat /etc/ntp.conf):

server 10.245.X.X
server 10.240.X.X
server 10.221.X.X
server 10.237.X.X
server 10.224.X.X

When reviewing the configuration file via SSH, the active setup shows a drift in the defined order of NTP servers. The /etc/ntp.conf file contains the NTP servers in an incorrect sequence/duplicate IP, even though VMware VAMI reflects a different configuration. This mismatch clearly indicates configuration drift. As a result, the management interface does not override these underlying file inconsistencies, leading to the discrepancy observed in the UI.

Resolution

To resolve this discrepancy, the configuration file must be manually aligned and the NTP service restarted.

1. Log in to the vCenter Server Appliance via SSH using root credentials.

2. Navigate to the shell: 

3. Create a backup of the current NTP configuration file:

   cp /etc/ntp.conf /etc/ntp.conf.bkp

4. Use a text editor (such as vi) to modify /etc/ntp.conf and ensure the server entries are listed in the preferred sequence and remove the duplicate IP:

   vi /etc/ntp.conf

5. Restart the NTP service to commit the changes:

   systemctl restart ntpd

6. Log in to the VAMI at https://<vCenter FQDN>:5480 and verify the NTP settings reflect the corrected sequence.