[iyunv@localhost chenshuo]# date
Sat May 28 16:38:02 EDT 2016
[iyunv@localhost chenshuo]# yum install ntp
Loaded plugins: fastestmirror, refresh-packagekit, security
Setting up Install Process
Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.yun-idc.com
* updates: mirrors.yun-idc.com
Package ntp-4.2.6p5-10.el6.centos.x86_64 already installed and latest version
Nothing to do
[iyunv@localhost chenshuo]# chkconfig ntpd on
[iyunv@localhost chenshuo]# ntpdate pool.ntp.org
28 May 08:42:10 ntpdate[28852]: step time server 182.92.12.11 offset -28590.133953 sec
[iyunv@localhost chenshuo]# date
Sat May 28 08:42:35 EDT 2016
[iyunv@localhost chenshuo]# service ntpd start
Starting ntpd: [ OK ]