我們都知道樹莓派的小巧和省電節省空間等太多的優勢，這裏就不一一列舉了，那麽樹莓派就需要長時間的運行，可以7×24的方式運行，那麽我們就把樹莓派當作一個小的服務器來運行，可以跑一些小的應用，例如可以在局域網中當作NTP服務器，哈哈，這個想法不錯！

初步設想：

1）樹莓派連接網絡之後，時間通過網絡自動同步，那麽樹莓派本身的時間就正常了。（不會的自己上網查，類似的文章一堆，不是本文重點）

2）在內部局域網中的其他計算機（包含win，Linux，mac等）都可以以樹莓派作為ntp服務器進行時間同步了。

一、配置局域網NTP服務器

1.安裝ntp服務

通過如下命令安裝ntp服務

2.修改配置文件ntp.conf

安裝完成後，打開/etc/ntp.conf文件，在命令處輸入：

cd /
cd etc/
sudo nano ntp.conf

顯示內容如下：

# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help

driftfile /var/lib/ntp/ntp.drift


# Enable this if you want statistics to be logged.
#statsdir /var/log/ntpstats/

statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable


# You 
 
do need to talk to an NTP server or two (or three).
#server ntp.your-provider.example

# pool.ntp.org maps to about 1000 low-stratum NTP servers.  Your server will
# pick a different set every time it starts up.  Please consider joining the
# pool: <http://www.pool.ntp.org/join.html>
server 0.debian.pool.ntp.org iburst
server 
 
1.debian.pool.ntp.org iburst
server 2.debian.pool.ntp.org iburst
server 3.debian.pool.ntp.org iburst


# Access control configuration; see /usr/share/doc/ntp-doc/html/accopt.html for
# details.  The web page <http://support.ntp.org/bin/view/Support/AccessRestrictions>
# might also be helpful.
#
# Note that "restrict" applies to both servers and clients, so a configuration
# that might be intended to block requests from certain clients could also end
# up blocking replies from your own upstream servers.

# By default, exchange time with everybody, but don‘t allow configuration.
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery

# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict ::1

# Clients from this (example!) subnet have unlimited access, but only if
# cryptographically authenticated.
#restrict 192.168.123.0 mask 255.255.255.0 notrust


# If you want to provide time to your local subnet, change the next line.
# (Again, the address is an example only.)
#broadcast 192.168.123.255

# If you want to listen to time broadcasts on your local subnet, de-comment the
# next lines.  Please do this only if you trust everybody on the network!
#disable auth
#broadcastclient

以上是安裝ntp服務完成後的默認配置。

3.重啟NTP服務

使用命令重啟ntp服務：sudo service ntp restart

4.本地測試

1）先確認ntp是否已啟動，命令：ps -ef | grep ntp，應該可以看到兩行內容（如果一行太長顯示不完，會顯示成兩行，註意分辨！）

2）命令行輸入：ntpq -p

結果如下，說明NTP服務器進程存在

pi@raspberrypi36:/ $ ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+cn.ntp.faelix.n 185.134.196.169  2 u    1   64  377  253.107   -7.402  23.282
+d.hnd.pobot.net 255.254.0.27     2 u   15   64  155  249.128   41.977   8.036
 static-5-103-13 .INIT.          16 u    -   64    0    0.000    0.000   0.000
*time5.aliyun.co 10.137.38.86     2 u    9   64  377   30.167    3.322   3.654

重啟系統

重啟命令：reboot

5.在其它PC同步樹莓派上的時間

在其它PC端填入我的樹莓派IP。
在Windows下即設置時間時選擇Internet時間，並填入樹莓派的IP。

=========================================================

參考：

https://blog.csdn.net/rk2900/article/details/8658110

https://www.linuxidc.com/Linux/2016-10/135945.htm

https://blog.csdn.net/gsls200808/article/details/51057359

在樹莓派是安裝並配置NTP服務