NTP同步

RedHat?Linux????NTP實施步驟
1、 查看本系統與NTP服務器的時間偏差

ntpdate -d 192.168.142.114

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[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

單位：秒
2、查看本系統之前是否配置過定時時間同步操作
?????

crontab -l

　　若有，應刪除?crontab?-e
3、查看本系統時區是否正確

date

???????若不正確，則應停應用，調整時區,可以參考tzselect
4、查看本系統之前是否配置過ntp服務命令

service ntpd status

???????若有過配置，應關閉NTP服務

service ntpd stop   

　　關閉NTP服務
5、確認NTP服務是否已經停止
???

 ntpq -p

6、編輯文件/etc/ntp.conf
注釋broadcastclient
#broadcastclient
需添加內容

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               ##如果使用緩慢調整應添加參數
driftfile /etc/ntp.drift    ##默認系統自帶，無需自己添加*/
tracefile /etc/ntp.trace

7、設置NTP服務開機自啟動

chkconfig ntpd on

9、重啟NTP服務

service ntpd restart

10、查看NTP運行狀態

ntpq -p 

顯示內容類似如下

     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

補充：直接對時命令
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ntpdate 192.168.142.114

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