1、配置一台时间服务器，让其它主机和时间服务器同步，并实现自动化任务每5分钟同步一次。
#Server：开启ntp
vi /etc/ntp.conf
driftfile /var/lib/ntp/drift
restrict default nomodify notrap nopeer noquery
restrict 127.0.0.1
restrict ::1
restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
server s1a.time.edu.cn
server s1b.time.edu.cn
server 202.120.2.101
includefile /etc/ntp/crypto/pw
keys /etc/ntp/keys
disable monitor
systemctl restart ntpd
#client
vi /etc/ntp.conf
driftfile /var/lib/ntp/drift
restrict default nomodify notrap nopeer noquery
restrict 127.0.0.1
restrict ::1
server 192.168.1.142
includefile /etc/ntp/crypto/pw
keys /etc/ntp/keys
disable monitor
crontab –e
*/5 * * * * /usr/sbin/ntpdate 192.168.1.142
