My comment was that PTP is a much better protocol than NTP, and in the doc they only talk about NTP:
https://docs.yugabyte.com/latest/deploy/checklist/#clock-syn...
https://docs.yugabyte.com/latest/deploy/checklist/#clock-syn...
As @aphyr had mentioned, any NTP-alike system would work. We can update the docs to mention PTP, we do work with AWS Time Sync as well (which uses Chrony).