ntpdate command:
ntpdate -u 210.72.145.44 : The network time synchronization command
I use here to do time synchronization with a machine in the cluster
[root@had]# ntpdate -u had
May 3 03:20:23 ntpdate[4454] : step time server 192.168.18.160 offset 154.003952 sec
[root@had]# date
Thu May 3 03:20:23 CST 2018
Note: If the -u parameter is not added, the following prompt will appear: no server suitable for synchronization found
-u: From man ntpdate, it can be seen that the -u parameter can bypass the firewall to synchronize with the host;
210.72.145.44: China National Timing Center Official server.
Common ntp server:
China National Time Service Center: 210.72.145.44
NTP server (Shanghai): ntp.api.bz
United States: time.nist.gov
Fudan: ntp.fudan.edu.cn
Microsoft Time Service Host (United States): time.windows.com
Taiwan Police University Time Service Center (Taiwan): asia.pool.ntp.org
It has been tested that the China National Time Service Center and the NTP Shanghai server can synchronize the time normally. Note that the -u parameter needs to be added!