主机时间同步阿里云

centos8: yum -y install chrony
centos7：yum -y install chrony

1. 同步主机： vim /etc/chrony.conf
修改为阿里云时间：
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server ntp.aliyun.com iburst
server ntp1.aliyun.com iburst 
配置允许其他主机同步你：
# Allow NTP client access from local network.
allow 192.168.159.0/24  

# Serve time even if not synchronized to a time source.
local stratum 10 # 建议开启, 此配置表示, 即使本机(NTP服务器)无法与互联网的NTP服务器进行同步, 也会继续给局域网内部的主机提供时间同步服务

启动服务：
ss -nlu

客户端时间同步

vim /etc/chrony.conf
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 192.168.159.217 iburst

重启：
systemctl restart chronyd

查看同步是否成功

chronyc sources -v