Overview

NTPDate is a breakpoint update for the time synchronization of your new instances. NTPD is a stepwise daemon for the time synchronization of your running instances. This document uses the CentOS 7.5 operating system as an example to introduce how to transition from NTPDate to NTPD on CVMs.

Prerequisites

The NTP service communicates on the port UDP 123. Please make sure that you have opened the port to the Internet before transitioning to the NTP service.
If the port has not been opened, please refer to Adding Security Group Policies to open it to the Internet.

Directions

Transitioning from NTPDate to NTPD manually

Shutting down NTPDate

1. Run the following command to export the crontab configuration and filter NTPDate.

   crontab -l |grep -v ntpupdate > /tmp/cronfile

2. Run the following command to update the NTPDate configuration.

   crontab /tmp/cronfile

3. Run the following command to modify the rc.local file.

   vim rc.local

4. Press i to switch to the editing mode and delete the ntpupdate configuration line.
5. Press Esc and enter :wq to save and close the file.

Configuring NTPD

1. Run the following command to open the configuration file of the NTP service.

   vi /etc/ntp.conf

2. Press i to switch to the editing mode and locate the server configurations. Change the value of server to the NTP clock source server you want to use (such as time1.tencentyun.com) and delete unwanted values, as shown below：
   
3. Press Esc and enter :wq to save and close the file.

Transitioning from NTPDate to NTPD automatically

1. Download the ntpd_enable.sh script.

   wget https://image-10023284.cos.ap-shanghai.myqcloud.com/ntpd_enable.sh

2. Run the following command to transition from NTPDate to NTPD using the ntpd_enable.sh script.

   sh ntpd_enable.sh