How to Sync Time on CentOS

To ensure that your system is always using the correct time, you can sync the hardware clock with a remote time server. This can be done in CentOS by using the NTP service which is not installed by default.

1. Install NTP service




[root@glt ~]# yum install ntp




2. Turn on service




[root@glt ~]# chkconfig ntpd on




3. Synchronize with time server in your zone

Continental Zones	URL
Europe	europe.pool.ntp.org
Asia	asia.pool.ntp.org
Oceania	oceania.pool.ntp.org
North America	north-america.pool.ntp.org
South America	south-america.pool.ntp.org
Africa	africa.pool.ntp.org




[root@glt ntp]# ntpdate  north-america.pool.ntp.org
 1 Oct 22:30:26 ntpdate[14429]: adjust time server 72.14.183.239 offset 0.011128 sec




4. Start the NTP service




[root@glt ~]# /etc/init.d/ntpd start




5. Verify that the NTP service is working




[root@glt ntp]#  ntpq -pn
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 +198.58.100.237  127.67.113.92    2 u   40   64    1   58.513   -0.780   0.002
 +151.236.20.4    193.190.230.65   2 u   39   64    1  260.159    5.373   0.002
 *66.175.216.101  127.67.113.92    2 u   38   64    1   81.630   -5.700   0.002