May 2018

Chrony is introduced as new NTP client to replace the ntp as the default time syncing package since RHEL7, so if you configure NTP during the installation process, it just enables the chronyd service, not ntpd service.

Even when you have enabled NTP to start on boot, it will not start when chrony 
is enabled. So to enable NTP to start on boot, we have to disable the chrony service

In case you want to use NTP only, then below is the procedure to do so :

1. Disable chronyd service.
    # systemctl stop chronyd
    # systemctl disable chronyd

2. Install NTP
    # yum install ntp (probably already installed)

3. Enable and Start NTPD Service
    # systemctl enable ntpd.service
    # systemctl start ntpd.service

4. Reboot and verify.
    # systemctl status ntpd.service
    
    ● ntpd.service - Network Time Service
   Loaded: loaded (/usr/lib/systemd/system/ntpd.service; enabled; vendor preset: disabled)
   Active: active (running) since Fri 2018-05-11 08:31:47 UTC; 13min ago
 Main PID: 1486 (ntpd)
   CGroup: /system.slice/ntpd.service
           └─1486 /usr/sbin/ntpd -u ntp:ntp -g

May 11 08:31:47 eri-4e-962955 systemd[1]: Starting Network Time Service...
May 11 08:31:47 eri-4e-962955 systemd[1]: Started Network Time Service.

Original Post Herehttps://www.thegeekdiary.com/centos-rhel-7-enable-ntp-to-start-at-boot-after-fresh-install-disable-chrony/ Original Post Herehttps://www.thegeekdiary.com/centos-rhel-7-enable-ntp-to-start-at-boot-after-fresh-install-disable-chrony/