我们都知道树莓派的小巧和省电节省空间等太多的优势，这里就不一一列举了，那么树莓派就需要长时间的运行，可以7×24的方式运行，那么我们就把树莓派当作一个小的服务器来运行，可以跑一些小的应用，例如可以在局域网中当作NTP服务器，哈哈，这个想法不错！
初步设想：
1）树莓派连接网络之后，时间通过网络自动同步，那么树莓派本身的时间就正常了。（不会的自己上网查，类似的文章一堆，不是本文重点）
2）在内部局域网中的其他计算机（包含win，Linux，mac等）都可以以树莓派作为ntp服务器进行时间同步了。
一、配置局域网NTP服务器
1.安装ntp服务
通过如下命令安装ntp服务
sudo apt-get install ntp
2.修改配置文件ntp.conf
安装完成后，打开/etc/ntp.conf文件，在命令处输入：
cd / cd etc/ sudo nano ntp.conf
显示内容如下：
# /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
以上是安装ntp服务完成后的默认配置。
3.重启NTP服务
使用命令重启ntp服务：sudo service ntp restart
4.本地测试
1）先确认ntp是否已启动，命令：ps -ef | grep ntp，应该可以看到两行内容（如果一行太长显示不完，会显示成两行，注意分辨！）
2）命令行输入：ntpq -p
结果如下，说明NTP服务器进程存在
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
重启系统
重启命令：reboot
5.在其它PC同步树莓派上的时间
在其它PC端填入我的树莓派IP。
在Windows下即设置时间时选择Internet时间，并填入树莓派的IP。
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参考：
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