Time Synchronization for CentOS7

Steps to set a server's time source to the NTP server:

1. timedatectl set-timezone UTC

2. In chronyd.conf, add or modify the following IP address setting.

   1. When using SCS, use the Swarm-internal IP address.
      server {SCS Swarm-internal IP address} iburst

   2. To use a different NTP server:
      server {NTP server IP} iburst
      NOTE:
      This must not be a Windows Directory SNTP server.

3. Restart chrony:

   > systemctl enable chronyd
   > systemctl restart chronyd

4. Verify that time sources are correct.
   chronyc sources
   Verify there is an asterisk (*) next to one of the lines, indicating the time has been synchronized. Example:

   210 Number of sources = 1
   MS Name/IP address Stratum Poll Reach LastRx Last sample
   ===============================================================================
   ^* telamon.tx.caringo.com 3 8 377 152 +5225ns[+7036ns] +/- 98ms

5. Once the time is synchronized, sync the BIOS clock.
   hwclock --systohc