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