服务端

1.安装chrony

$yum -y install chrony

2.备份ntp服务器配置文件

$cp /etc/chrony.conf /etc/chrony.conf.bak

3.修改配置

$cat >/etc/chrony.conf <<'EOF'
server s1a.time.edu.cn iburst
server ntp.aliyun.com iburst
#server 172.16.1.71 iburst   #(同步本地时间)
driftfile /var/lib/chrony/drift
makestep 1.0 3
rtcsync
allow 172.16.1.0/24
local stratum 10
logdir /var/log/chrony
EOF

4.开机自启并启动chronyd服务

$systemctl enable chronyd
$systemctl start chronyd

5.查看端口

$netstat -antulp | grep chronyd
udp        0      0 127.0.0.1:323           0.0.0.0:*                           1771/chronyd        
udp        0      0 0.0.0.0:123             0.0.0.0:*                           1771/chronyd        
udp6       0      0 ::1:323                 :::*                                1771/chrony

6.查看是否同步(带*是同步成功)

$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               
===============================================================================
^* 60.10.112.202.in-addr.ar>     1  10   377   948  +1431us[+1700us] +/-   21ms

客户端测试

#1.更改时间
$date -s 20190825
    
#2.同步测试
$ntpdate 172.16.1.*

#3.书写定时任务
$echo "*/5 * * * * /sbin/ntpdate 172.16.1.71 >/dev/null 2>&1" >> /var/spool/cron/root