实验环境

两台linux（centos7.4） 服务端192.168.50.80 客户端192.168.50.81

SELINUX关闭

防火墙关闭（避免端口问题导致的时间不同步）

配置好yum源

1.在服务端和客户端都安装上chrony。

yum install chrony

2.修改服务器端chrony配置

[root@192.168.50.81 ~]# 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 ntp1.aliyun.com iburst
server ntp2.aliyun.com iburst
server ntp3.aliyun.com iburst
server ntp4.aliyun.com iburst
server ntp5.aliyun.com iburst

# Record the rate at which the system clock gains/losses time.
driftfile /var/lib/chrony/drift

# Allow the system clock to be stepped in the first three updates
# if its offset is larger than 1 second.
makestep 1.0 3

# Enable kernel synchronization of the real-time clock (RTC).
rtcsync

# Enable hardware timestamping on all interfaces that support it.
#hwtimestamp *

# Increase the minimum number of selectable sources required to adjust
# the system clock.
#minsources 2

# Allow NTP client access from local network.
allow 0.0.0.0/0

# Serve time even if not synchronized to a time source.
local stratum 10

# Specify file containing keys for NTP authentication.
#keyfile /etc/chrony.keys

# Specify directory for log files.
logdir /var/log/chrony

# Select which information is logged.
#log measurements statistics tracking

3.保存并启用服务端chrony

systemctl start chronyd
systemctl enable chronyd

4.查看时间服务是否生效

[root@192.168.50.81 ~]# chronyc sources -v

210 Number of sources = 2

  .-- 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               
===============================================================================
^+ 120.25.115.20                 2   7   377   332   +289us[ +458us] +/-   22ms
^* 203.107.6.88                  2   7   377    74  +3017us[+3362us] +/-   17ms

5.配置客户端

[root@192.168.50.81 ~]# 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 192.168.50.80 iburst

# Record the rate at which the system clock gains/losses time.
driftfile /var/lib/chrony/drift

# Allow the system clock to be stepped in the first three updates
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 192.168.50.80 iburst

# Record the rate at which the system clock gains/losses time.
driftfile /var/lib/chrony/drift

# Allow the system clock to be stepped in the first three updates
# if its offset is larger than 1 second.
makestep 1.0 3

# Enable kernel synchronization of the real-time clock (RTC).
rtcsync

# Enable hardware timestamping on all interfaces that support it.
#hwtimestamp *

# Increase the minimum number of selectable sources required to adjust
# the system clock.
#minsources 2

# Allow NTP client access from local network.
#allow 192.168.50.0/24

# Serve time even if not synchronized to a time source.
#local stratum 10

# Specify file containing keys for NTP authentication.
#keyfile /etc/chrony.keys

# Specify directory for log files.
logdir /var/log/chrony

# Select which information is logged.

#log measurements statistics tracking

6.保存并启用客户端

systemctl start chronyd
systemctl enable chronyd

7.客户端同步服务端时间并写入硬件配置

[root@192.168.50.81 ~]# ntpdate 192.168.50.80
[root@192.168.50.81 ~]# hwclock -w