Add or Replace NTP Servers in the vCenter Server Configuration

To set up the vCenter Server to use NTP-based time synchronization, you must add the NTP servers to the vCenter Server configuration.

Procedure

Access the appliance shell and log in as a user who has the administrator or super administrator role.
The default user with super administrator role is root.
Add NTP servers to the vCenter Server configuration by running the following ntp.set command.
```
ntp.set --servers IP-addresses-or-host-names
```
In this command, IP-addresses-or-host-names is a comma-separated list of IP addresses or host names of the NTP servers.

This command removes the current NTP servers (if any) and adds the new NTP servers to the configuration. If the time synchronization is based on an NTP server, then the NTP daemon is restarted to reload the new NTP servers. Otherwise, this command replaces the current NTP servers in the NTP configuration with the new NTP servers you specify.
(Optional) To verify that you successfully applied the new NTP configuration settings, run the following command.
```
ntp.get
```
The command returns a space-separated list of the servers configured for NTP synchronization. If the NTP synchronization is enabled, the command returns that the NTP configuration is in Up status. If the NTP synchronization is disabled, the command returns that the NTP configuration is in Down status.
(Optional) To verify if the NTP server is reachable, run the following command.
```
ntp.test --servers IP-addresses-or-host-names
```
The command returns the status of the NTP servers.

If the NTP synchronization is disabled, you can configure the time synchronization settings in the vCenter Server to be based on an NTP server. See Synchronize the Time in vCenter Server with an NTP Server.