使用nginx作为tcp代理的安装配置例子

   以前一般代理tcp时候，都选用haproxy。nginx 1.9 之后，就多了一个选择。可以使用nginx做代理。这样大家也不用重新去熟悉haproxy。
tcp 代理本质是 端口到端口映射转发，比较简单。没有http层代理那么复杂。我一般用来代理https，大家都知道，以前使用nginx 代理https要配置证书等各种琐事。然而对于tcp层来说，没有证书一说。纯粹转发简单干净的配置，非常的爽; 当然有时候也用tcp替换http层代理。原因是tcp代理配置更加简单，性能也更高。

一、nginx 下载安装

方式一：下载地址：http://nginx.org/en/download.html

方式二：通过rpm包安装

1、添加安装源，在/etc/yum.repos.d底下创建文件nginx.repo

1. [nginx]
2. name=nginx repo
3. baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
4. gpgcheck=0
5. enabled=1

如果是ubuntu
添加安装源 /etc/apt/sources.list.d/nginx.list， 文件内容为

1. deb http://nginx.org/packages/ubuntu/ xenial nginx

2. deb-src http://nginx.org/packages/ubuntu/ xenial nginx

2、安装nginx

1. #yum clean all
2. #yum install nginx

如果是ubuntu

1. #sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys $key
   #sudo apt-get update
   #sudo apt-get install nginx

3、查看安装路径和版本

1. #whereis nginx
2. #/usr/sbin/nginx -v
3. nginx version: nginx/1.10.1

4、查看缺省配置文件路径

1. #/usr/sbin/nginx -h
2. -c filename : set configuration file (default: /etc/nginx/nginx.conf)

二、nginx配置

1、目录规划

1. mkdir -p /opt/service/nginx/conf
2. mkdir -p /opt/logs/nginx
3. cd /opt/service/nginx
4. ln -s /usr/sbin/nginx
5. ln -s /opt/logs/nginx log

/opt/service/nginx/
├── conf
├── log -> /opt/logs/nginx
└── nginx -> /usr/sbin/nginx

2、配置nginx.conf

1. user nginx;
2. worker_processes 16;
3. worker_rlimit_nofile 100000;
5. error_log /opt/service/nginx/log/error.log error;
6. pid /opt/service/nginx/nginx.pid;
7. 
   events {
8.     use epoll;
9.     worker_connections 10240;
10. }
12. include /opt/service/nginx/conf/*.conf;

3、配置tcp 代理 
/opt/service/nginx/conf/nginx_tcp_proxy.conf

1. stream {
2. #---------------------------------------------------------------------
3. # tcp 代理
4. #---------------------------------------------------------------------
5. upstream weixin_proxy {
6. hash $remote_addr consistent;
7. server wx.qq.com:443 weight=1 max_fails=3 fail_timeout=60s;
8. }
10. server {
11. listen 443;
12. proxy_connect_timeout 10s;
13. proxy_pass weixin_proxy;
14. proxy_buffer_size 64k;
15. }
16. }

三、启动维护nginx

1、编辑 nginx.sh

1. #!/bin/sh
   
2. # description:nginx server
   
3. # nginx - this script is used to control nginx service
   
4. # processname nginx
   
5. # nginx version: nginx/1.10.1
   
6.  
   
7. nginx="/usr/sbin/nginx"
   
8. prog="nginx"
   
9. conf_file="/etc/nginx/nginx.conf"
   
10.  
    
11. start() {
    
12.     if [ `pgrep $prog | wc -l` -eq 2 ];then
    
13.         if [ -x $nginx ] && [ -f $conf_file ];then
    
14.             $nginx -c $conf_file
    
15.             ret=$?
    
16.             if [ $ret -eq 0 ];then
    
17.                 echo "$prog start successed"
    
18.             else
    
19.                 echo "$prog start failed"
    
20.             fi
    
21.         else
    
22.             echo "$prog config file not exist"
    
23.         fi
    
24.     else
    
25.         num=`pgrep $prog `
    
26.         echo "$prog is already started ... $num "
    
27.     fi
    
28. }
    
29.  
    
30.  
    
31. stop() {
    
32.     if [ `pgrep $prog | wc -l` -ne 2 ];then
    
33.         killall -9 $prog
    
34.         ret=$?
    
35.         if [ $ret -eq 0 ];then
    
36.             echo "$prog stop successed"
    
37.         else
    
38.             echo "$prog stop failed"
    
39.         fi
    
40.     else
    
41.         echo "$prog is already stopped ..."
    
42.     fi
    
43. }
    
44.  
    
45. restart() {
    
46.     stop
    
47.     sleep 2
    
48.     start
    
49. }
    
50.  
    
51. reload() {
    
52.     if [ `pgrep $prog | wc -l` -ne 0 ];then
    
53.         pid=`ps -ef | grep $prog | grep master | awk '{print $2}'`
    
54.         if [ -x $nginx ] && [ -f $conf_file ];then
    
55.             kill -HUP $pid
    
56.             ret=$?
    
57.             if [ $ret -eq 0 ];then
    
58.                 echo "$prog reload successed"
    
59.             else
    
60.                 echo "$prog reload failed"
    
61.             fi
    
62.         else
    
63.             echo "$prog config file is not exist"
    
64.         fi
    
65.     else
    
66.         echo "$prog is stopped, please start $prog first ..."
    
67.     fi
    
68. }
    
69.  
    
70. check() {
    
71.     if [ -x $nginx ] && [ -f $conf_file ];then
    
72.         $nginx -t -c $conf_file
    
73.         ret=$?
    
74.         if [ $ret -eq 0 ];then
    
75.             echo "$prog check successed"
    
76.         else
    
77.             echo "$prog check failed"
    
78.         fi
    
79.     else
    
80.         echo "$prog program or config file not exit!"
    
81.     fi
    
82. }
    
83.  
    
84. case $1 in
    
85.     start)
    
86.         start
    
87.         ;;
    
88.     stop)
    
89.         stop
    
90.         ;;
    
91.     restart)
    
92.         restart
    
93.         ;;
    
94.     reload)
    
95.         reload
    
96.         ;;
    
97.     check)
    
98.         check
    
99.         ;;
    
100.     *)
     
101.         echo "Usage: $0 {start|stop|restart|reload|check}"
     
102. esac

2、启动 nginx.sh

1. chmod a+rwx nginx.sh
2. ./nginx.sh restart

整个目录结构如下

1. # ll
   
2. total 8
   
3. drwxr-xr-x 2 root root 33 Dec 21 17:16 conf
   
4. lrwxrwxrwx 1 root root 15 Dec 21 17:00 log -> /opt/logs/nginx
   
5. lrwxrwxrwx 1 root root 15 Dec 21 16:59 nginx -> /usr/sbin/nginx
   
6. -rw-r--r-- 1 root root 6 Dec 21 17:21 nginx.pid
   
7. -rwxrwxrwx 1 root root 2172 Dec 21 17:20 nginx.sh

问题：
当代理的后端是域名的时候，域名的dns发生变化。nginx并不知道。看文档nginx提供了定时刷新dns的功能，但是我配置好像没有起到作用。
在 nginx.conf 尾部加上这个配置
    resolver  100.100.2.136 valid=1s;
    include /etc/nginx/nginx_vhost/*.conf;