一、安装ntpd

查看状态
sudo systemctl status ntpd
启动
sudo systemctl start ntpd
开机自启
sudo systemctl is-enabled ntpd

    sudo systemctl enable ntpd

　配置

     $ sudo vim /etc/ntp.conf

          第一处：修改成自己的网段

          #Hosts on local network are less restricted.

          restrict 192.168.74.0 mask 255.255.255.0 nomodify notrap

          第二处：由于是内网环境，就不需要这些服务配置，注释

          # Please consider joining the pool  (http://www.pool.ntp.org/join.html).

          # server 0.centos.pool.ntp.org

          # server 1.centos.pool.ntp.org

          # server 2.centos.pool.ntp.org

          第三处：ntp server提供的本地服务

          server 127.127.1.0                     #local clock

          fudge 127.127.1.0   stratum  10



从机同步时间
sudo ntpdate hadoop101