yum list |grep ntpd yum -y install ntp systemctl start ntpd systemctl status ntpd systemctl enable ntpd systemctl list-unit-files|grep ntpd
yum确认是否安装yum安装启动ntpd服务查看状态设置开机启动查看是否设置开机启动
centos7 安装ntp服务并启动，设置开机重启
原文：https://blog.51cto.com/11263100/2453322
