This page https://docs.hortonworks.com/HDPDocuments/Ambari-2.6.2.2/bk_ambari-installation/content/enable_ntp_o... instructs to install ntpd even if using RHEL7/CentOS7.
As far as I know, Chrony is the default in RHEL7/CentOS7 instead of ntpd.
Why does that document instruct to install ntpd?
Is there any reason not to use (or recommend) Chrony?