How to configure the NTP Daemon to keep a RHEL 7-based server's time accurate

Introduction

This article provides the steps to configure the NTP daemon to keep a RHEL 7-based server's time accurate.

Procedure

1. Access the server's command line as the 'root' user via SSH or "Terminal" in WHM.

2. Stop and disable the cronyd service.

   # systemctl stop chronyd; systemctl disable chronyd

3. Install the ntp package.

   # yum install ntp -y

4. Enable the ntpd service.

   # systemctl enable ntpd

5. Open outbound UDP port 123 in all applicable firewall and security services.
6. Open the /etc/ntp.conf file in your preferred text editor.

7. Comment out the existing server lines.

   # server 0.centos.pool.ntp.org iburst
   # server 1.centos.pool.ntp.org iburst
   # server 2.centos.pool.ntp.org iburst
   # server 3.centos.pool.ntp.org iburst

8. Add a new server line for the hostname of the NTP server to query.

   # server time.google.com

9. Save the changes and exit the text editor.

10. Start the ntpd service.

    # systemctl start ntpd

Additional resources

Chapter 19. Configuring NTP Using ntpd: 19.17. Configure NTP