In my opinion ntp should be replaced by chrony.     Benefits of Chrony include: 1. Faster synchronization requiring only minutes instead of hours to minimize the time and frequency error, which is useful on desktops or systems not running 24 hours a day. 2. Better response to rapid changes in the clock frequency, which is useful for virtual machines that have unstable clocks or for power-saving technologies that don’t keep the clock frequency constant. 3. After the initial s