一、centos 7

yum -y install ntpdate

ntpdate ntp1.aliyun.com

crontab -e

01 01 * * * /usr/sbin/ntpdate ntp1.aliyun.com

二、centos 8

yum -y install chrony

//注释pool 2.centos.pool.ntp.org iburst
sed -i 's/^pool 2.centos.pool.ntp.org iburst/#&/' /etc/chrony.conf
//添加三个阿里云NTP的服务器
echo -e "server ntp1.aliyun.com iburst\nserver ntp2.aliyun.com iburst\nserver ntp3.aliyun.com iburst" | sudo tee -a /etc/chrony.conf

systemctl restart chronyd

systemctl enable chronyd