Network Time Protocol

$ sudo yum install chrony

$ sudo systemctl is-active chronyd

active

$ sudo systemctl is-active ntpd

active

$ sudo systemctl enable ntp.service

$ sudo systemctl enable ntpd.service

maxpoll 

server

pool

• if the system is configured to use the chronyd as the NTP daemon (the default), edit the file /etc/chrony.conf as follows,
• if the system is configured to use the ntpd as the NTP daemon, edit the file /etc/ntp.conf as documented below.

server ntpserver

• if the system is configured to use the chronyd as the NTP daemon (the default), edit the file /etc/chrony.conf as follows,
• if the system is configured to use the ntpd as the NTP daemon, edit the file /etc/ntp.conf as documented below.

server ntpserver

server <remote-server>

restrict -4 default kod nomodify notrap nopeer noquery

restrict -6 default kod nomodify notrap nopeer noquery

OPTIONS="-u ntp:ntp"

server ntpserver

server ntpserver