linux centos7 安装ntp服务并启动，设置开机重启

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