NTP同步

RedHat Linux NTP实施步骤
1、查看本系统与NTP服务器的时间偏差

ntpdate -d 192.168.142.114

[root@zabbix-proxy ~]# ntpdate -d 192.168.142.114
24 Aug 17:26:45 ntpdate[3355]: ntpdate 4.2.6p5@1.2349-o Fri Apr 13 12:52:28 UTC 2018 (1)
Looking for host 192.168.142.114 and service ntp
host found : 192.168.142.114
transmit(192.168.142.114)
receive(192.168.142.114)
transmit(192.168.142.114)
receive(192.168.142.114)
transmit(192.168.142.114)
receive(192.168.142.114)
transmit(192.168.142.114)
receive(192.168.142.114)
server 192.168.142.114, port 123
stratum 1, precision -18, leap 00, trust 000
refid [MRS], delay 0.02600, dispersion 0.00003
transmitted 4, in filter 4
reference time:    df2a4dd8.09606edb  Fri, Aug 24 2018 17:26:48.036
originate timestamp: df2a4ddb.fbbb6da2  Fri, Aug 24 2018 17:26:51.983
transmit timestamp:  df2a4ddb.fb8df6df  Fri, Aug 24 2018 17:26:51.982
filter delay:  0.02602  0.02603  0.02600  0.02614 0.00000  0.00000  0.00000  0.00000 
filter offset: -0.00005 -0.00002 0.000006 0.0000370.000000 0.000000 0.000000 0.000000
delay 0.02600, dispersion 0.00003
offset 0.00000624 Aug 17:26:51 ntpdate[3355]: adjust time server 192.168.142.114 offset 0.000006 sec

单位：秒
2、查看本系统之前是否配置过定时时间同步操作

crontab -l

　　若有，应删除 crontab -e
3、查看本系统时区是否正确

date

若不正确，则应停应用，调整时区,可以参考tzselect
4、查看本系统之前是否配置过ntp服务命令

service ntpd status

若有过配置，应关闭NTP服务

service ntpd stop

　　关闭NTP服务
5、确认NTP服务是否已经停止

 ntpq -p

6、编辑文件/etc/ntp.conf
注释broadcastclient
#broadcastclient
需添加内容

server 192.168.150.142 minpoll 4 maxpoll 4 prefer
##maxpoll 4：2^4(16s)同步一次
server 192.168.150.143 minpoll 4 maxpoll 4
tinker step 0               ##如果使用缓慢调整应添加参数
driftfile /etc/ntp.drift    ##默认系统自带，无需自己添加*/
tracefile /etc/ntp.trace

7、设置NTP服务开机自启动

chkconfig ntpd on

9、重启NTP服务

service ntpd restart

10、查看NTP运行状态

ntpq -p

显示内容类似如下

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================192.168.142.114 .MRS.            1 u    8   16    1    0.403    0.037   0.000192.168.142.224 .INIT.          16 u    -   16    0    0.000    0.000   0.000