chrony是网络时间协议（NTP）的通用实现,chrony中包含两个程序，chronyd是一个可以在启动时启动的守护程序，chronyc是一个命令行界面程序。

配置文件：chrony.conf
server：时间服务器地址；
allow ：允许客户端；
deny ：拒绝客户端；；
local stratum 10：即使自己未能同步网络时间，也允许授时给其它客户端；

环境

CentOS Linux release 7.6
server： 10.120.123.8
client ： 10.120.123.9

安装Chrony

yum install -y chrony

server端(10.120.123.8)

配置文件

vim/etc/chrony.conf
allow 10.120.123.0/24

启动服务

systemctl start chronyd.service
systemctl enable chronyd.service

查看端口

netstat -nlup | grep chronyd 
udp        0      0 0.0.0.0:123             0.0.0.0:*                           9091/chronyd        
udp        0      0 127.0.0.1:323         0.0.0.0:*                           9091/chronyd        
udp6      0      0 ::1:323                     :::*                                   9091/chronyd

client端(10.120.123.9)

配置文件

vim/etc/chrony.conf
server 10.120.123.8 iburst
#server 0.centos.pool.ntp.org iburst
#server 1.centos.pool.ntp.org iburst
#server 2.centos.pool.ntp.org iburst
#server 3.centos.pool.ntp.org iburst

启动服务

systemctl start chronyd.service
systemctl enable chronyd.service

查看同步状态

1,chronyc sourcestats

210 Number of sources = 1
Name/IP Address            NP  NR  Span  Frequency  Freq Skew  Offset  Std Dev
==============================================================================
10.120.123.8                0   0     0     +0.000   2000.000     +0ns  4000ms

2.chronyc sources -v

210 Number of sources = 1

  .-- Source mode  ‘^‘ = server,‘=‘ = peer,‘#‘ = local clock.
 / .- Source state ‘*‘ = current synced,‘+‘ = combined,‘-‘ = not combined,| /   ‘?‘ = unreachable,‘x‘ = time may be in error,‘~‘ = time too variable.
||                                                 .- xxxx [ yyyy ] +/- zzzz
||      Reachability register (octal) -.           |  xxxx = adjusted offset,||      Log2(Polling interval) --.      |          |  yyyy = measured offset,||                                     |          |  zzzz = estimated error.
||                                 |    |           MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================