Synchronize with the clock server provided on the Internet when connected to the Internet
Synchronization command: ntpdate ntp4.aliyun.com (a free time server provided by Alibaba Cloud)
Configure clock synchronization in offline state
1. Set the time of the clock synchronization server (node03 2012-12-12 12:12:12)
Synchronize node01 node02 time with node03
2. Modify the first configuration file /etc/ntp.conf
Add the following content
restrict 192.168.100.0 mask 255.255.255.0 nomodify notrap server 127.127.1.0 # localclock fudge 127.127.1.0 stratum 10
Annotate future servers
#server 0.centos.pool.ntp.org iburst #server 1.centos.pool.ntp.org iburst #server 2.centos.pool.ntp.org iburst #server 3.centos.pool.ntp.org iburst
3. Modify the second configuration file vi /etc/sysconfig/ntpd
Add the following content
SYNC_HWLOCK=yes
4. Restart the ntp service
/etc/init.d/ntpd restart
5. Clock synchronization
Synchronize on node01 node02
Command ntpdate node03 (clock server)
ntpdate 192.168.100.133 (clock server)