linux下时区设置和时间同步

一、时区设置：

[root@master ~]# tzselect
Please identify a location so that time zone rules can be set correctly.
Please select a continent or ocean.
 1) Africa
 2) Americas
 3) Antarctica
 4) Arctic Ocean
 5) Asia
 6) Atlantic Ocean
 7) Australia
 8) Europe
 9) Indian Ocean
10) Pacific Ocean
11) none - I want to specify the time zone using the Posix TZ format.
#? 5
Please select a country.
 1) Afghanistan           18) Israel                35) Palestine
 2) Armenia               19) Japan                 36) Philippines
 3) Azerbaijan            20) Jordan                37) Qatar
 4) Bahrain               21) Kazakhstan            38) Russia
 5) Bangladesh            22) Korea (North)         39) Saudi Arabia
 6) Bhutan                23) Korea (South)         40) Singapore
 7) Brunei                24) Kuwait                41) Sri Lanka
 8) Cambodia              25) Kyrgyzstan            42) Syria
 9) China                 26) Laos                  43) Taiwan
10) Cyprus                27) Lebanon               44) Tajikistan
11) East Timor            28) Macau                 45) Thailand
12) Georgia               29) Malaysia              46) Turkmenistan
13) Hong Kong             30) Mongolia              47) United Arab Emirates
14) India                 31) Myanmar (Burma)       48) Uzbekistan
15) Indonesia             32) Nepal                 49) Vietnam
16) Iran                  33) Oman                  50) Yemen
17) Iraq                  34) Pakistan
#? 9
Please select one of the following time zone regions.
1) Beijing Time
2) Xinjiang Time
#? 1

The following information has been given:

        China
        Beijing Time

Therefore TZ='Asia/Shanghai' will be used.
Local time is now:      Sun Apr 15 09:16:02 CST 2018.
Universal Time is now:  Sun Apr 15 01:16:02 UTC 2018.
Is the above information OK?
1) Yes
2) No
#? 1

You can make this change permanent for yourself by appending the line
        TZ='Asia/Shanghai'; export TZ
to the file '.profile' in your home directory; then log out and log in again.

Here is that TZ value again, this time on standard output so that you
can use the /usr/bin/tzselect command in shell scripts:
Asia/Shanghai
You have new mail in /var/spool/mail/root

然后再配置环境变量

[root@master ~]# vi /etc/profile

###NTP
export TZ='Asia/Shanghai'

然后reboot 

看下时间，我用的是CST（china-shanghai） ，没用UTC ， UTC是世界协调时间，比北京时间晚8个小时

[root@master ~]# date
Sun Apr 15 09:18:01 CST 2018

二、 时间同步：

[root@master ~]# ntpdate ntp1.aliyun.com
15 Apr 09:21:06 ntpdate[2557]: adjust time server 182.92.12.11 offset -0.088385 sec

三、其他

如果想保证时间更精确，可以在局域网内设置一个服务器采用上述方式获取时间。

然后将其他的 服务器同步此台服务器的时间。

该方式请参看 https://blog.csdn.net/leys123/article/details/52937114