基于CentOS 7配置Nginx反向代理

Nginx作为反向代理服务器被广泛使用在各大互联网企业。它简单易用，可以根据业务的需求将其不同的业务类型代理至不同的服务器，将整个站点请求压力按类型分摊到不同的服务器。该方式使的整个站点请求性能得以极大的提升。本文简要描述了Nginx几种不同情形的代理演示，供大家参考。

一、反向代理及演示环境描述

1、反向代理

在计算机网络中，反向代理是一种代理服务器，代表客户端从一个或多个服务器检索资源。然后将这些资源返回给客户机，就像它们源自Web服务器本身一样。与正向代理相反，正向代理是与其关联的客户端联系任何服务器的中介，反向代理是任何客户端与其关联的服务器进行联系的中介。

有关正向代理可参考：基于CentOS 7配置Nginx正向代理

2、本演示中的几个服务器

二、常规反向代理配置

1、后端服务器配置(Apache)

后端Apache服务器主机名及IP
  # hostname
  centos7-web.example.com
  # more /etc/redhat-release
  CentOS Linux release 7.2.1511 (Core)
  # ip addr|grep inet|grep global
  inet 172.24.8.128/24 brd 172.24.8.255 scope global eno16777728

  # systemctl start httpd.service
  # echo "This is a httpd test page.">/var/www/html/index.html
  # curl http://localhost
  This is a httpd test page.

2、前端Nginx反向代理服务器配置

前端Nginx服务器主机名及IP
  # hostname
  centos7-router

  # more /etc/redhat-release
  CentOS Linux release 7.2.1511 (Core)
  # ip addr |grep inet|grep global
  inet 172.24.8.254/24 brd 172.24.8.255 scope global eno16777728
  inet 192.168.1.175/24 brd 192.168.1.255 scope global dynamic eno33554960

Nginx版本
  # nginx -V
  nginx version: nginx/1.10.2

添加一个新的配置文件用作反向代理
  # vim /etc/nginx/conf.d/reverse_proxy.conf
  server {
    listen 8090;
    server_name localhost;

  location / {
    proxy_pass http://172.24.8.128; ###反向代理核心指令

    proxy_buffers 256 4k;
    proxy_max_temp_file_size 0;
    proxy_connect_timeout 30;

    proxy_cache_valid 200 302 10m;
    proxy_cache_valid 301 1h;
    proxy_cache_valid any 1m;
    }
  }

# systemctl reload nginx
# ss -nltp|grep nginx|grep 8090
LISTEN 0 128 *:8090 *:* users:(("nginx",pid=78023,fd=8),("nginx",pid=78021,fd=8))

# curl http://localhost:8090 ##基于本地测试
This is a httpd test page.

查看Apache服务器日志
# more /var/log/httpd/access_log ##请求IP地址为172.24.8.254，当从其他机器请求时也是172.24.8.254这个IP
172.24.8.254 - - [30/Oct/2017:14:02:38 +0800] "GET / HTTP/1.0" 200 27 "-" "curl/7.29.0"

3、反向代理服务器及后端服务器日志格式设置

为Nginx服务器添加proxy_set_header指令，修改后如下
  # grep proxy_set_header -B2 /etc/nginx/conf.d/reverse_proxy.conf
  location / {
    proxy_pass http://172.24.8.128;
    proxy_set_header X-Real-IP $remote_addr;
    }
  # systemctl reload nginx.service

后端服务器Apache日志格式设置

  # vim /etc/http/conf/httpd.conf

    # LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined #注释此行，添加下一行
    LogFormat "%{X-Real-IP}i %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined #关键描述 {X-Real-IP}i

  # ip addr|grep inet|grep global    #从1.132主机访问
  inet 192.168.1.244/24 brd 192.168.1.255 scope global eth0

  # curl http://192.168.1.175:8090  #从1.244主机访问
  This is a httpd test page

#再次查看apache访问日志，如下，不再是代理服务器IP地址，此时显示为1.244
  192.168.1.244 - - [30/Oct/2017:15:49:07 +0800] "GET / HTTP/1.0" 200 27 "-" "curl/7.19.7 (x86_64-redhat-linux-gnu)
  libcurl/7.19.7 NSS/3.14.0.0 zlib/1.2.3 libidn/1.18 libssh2/1.4.2"

二、基于目录匹配反向代理

后端服务器采用Nginx的配置

  # more /etc/redhat-release ##os平台及ip地址
  CentOS release 6.7 (Final)
  # ip addr|grep eth0|grep global
  inet 192.168.1.132/24 brd 192.168.1.255 scope global eth0
  # nginx -v ##nginx版本
  nginx version: nginx/1.10.2

  # mkdir -pv /usr/share/nginx/html/images ##创建图片目录
  mkdir: created directory `/usr/share/nginx/html/images'

  # cp /usr/share/backgrounds/nature/*.jpg /usr/share/nginx/html/images/. ##复制图片文件

  # cp /etc/nginx/conf.d/default.conf /etc/nginx/conf.d/default.conf.bk
  # vim /etc/nginx/conf.d/default.conf ##此处直接修改缺省配置文件

  server {
  listen 80 default_server;
  listen [::]:80 default_server;
  server_name _;
  root /usr/share/nginx/html;

  # Load configuration files for the default server block.
  include /etc/nginx/default.d/*.conf;

  location / {
    }

  location /images {
    alias /usr/share/nginx/html/images; ##此处配置了别名
    }

  error_page 404 /404.html;
  location = /40x.html {
    }

  error_page 500 502 503 504 /50x.html;
  location = /50x.html {
    }
  }

# /etc/init.d/nginx reload
Reloading nginx: [ OK ]

前端Nginx配置
  # vim /etc/nginx/conf.d/reverse_proxy.conf
  server {
  listen 8090;
  server_name localhost;

  location / {
    proxy_pass http://172.24.8.128;
    proxy_set_header X-Real-IP $remote_addr;
    }

  location /images { ##将images目录下的文件代理至192.168.1.132
    proxy_pass http://192.168.1.132;
    proxy_set_header X-Real-IP $remote_addr;
    }
  }

# systemctl reload nginx

验证代理情况
在ip为192.168.1.244测试对images目录下的jpg文件请求(基于浏览器查看jpg成功，此处省略贴图)
  # ip addr|grep inet|grep global
  inet 192.168.1.244/24 brd 192.168.1.255 scope global eth0
  # curl -I http://192.168.1.175:8090/images/Garden.jpg
  HTTP/1.1 200 OK
  Server: nginx/1.12.2
  Date: Tue, 31 Oct 2017 01:48:18 GMT
  Content-Type: image/jpeg
  Content-Length: 264831
  Connection: keep-alive
  Last-Modified: Mon, 30 Oct 2017 08:21:28 GMT
  ETag: "59f6e108-40a7f"
  Accept-Ranges: bytes

三、基于特定文件类型的反向代理配置

php服务器端配置(ip 192.168.1.132)

  # ss -nltp|grep php
  LISTEN 0 128 192.168.1.132:9000 *:* users:(("php-fpm",7147,8),("php-fpm",7148,0),("php-fpm",7149,0))

  # mkdir -pv /data ###存放php代码
  # echo "/data 192.168.1.0/24(rw)" >/etc/exports
  # /etc/init.d/rpcbind start
  # /etc/init.d/nfslock start
  # /etc/init.d/nfs start

  # echo "<?php phpinfo();?>" > /data/index.php

Nginx代理端配置(ip 192.168.1.175)
  # mkdir /data
  # mount -t nfs 192.168.1.132:/data /data
  # ls /data
  index.php

  # vim /etc/nginx/conf.d/reverse_proxy.conf
  server {
  listen 8090;
  server_name localhost;

  location / {
    proxy_pass http://172.24.8.128;
    proxy_set_header X-Real-IP $remote_addr;
    }

  location /images {
    proxy_pass http://192.168.1.132;
    proxy_set_header X-Real-IP $remote_addr;
    }

  location ~ \.php$ {
    root /data;
    fastcgi_pass 192.168.1.132:9000;
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
    include fastcgi_params;
    }
  }

# systemctl restart nginx

测试反向代理至php
  [root@ydq05 ~]# ip addr|grep inet|grep global
  inet 192.168.1.244/24 brd 192.168.1.255 scope global eth0
  [root@ydq05 ~]# curl -I http://192.168.1.175:8090/index.php
  HTTP/1.1 200 OK
  Server: nginx/1.12.2
  Date: Tue, 31 Oct 2017 03:22:59 GMT
  Content-Type: text/html; charset=UTF-8
  Connection: keep-alive
  X-Powered-By: PHP/5.6.0

四、基于upstream 配置反向代理至tomcat

Nginx upstream指令也可以将请求代理到后端服务器
如下示例，结合upstream指令演示将其代理到tomcat

# vim /etc/nginx/conf.d/tomcat.conf 
upstream app {
                server localhost:8080;
                keepalive 32;
}

server {
    listen 80;
    server_name localhost;
    location / {
        proxy_set_header Host $host;
        proxy_set_header x-for $remote_addr;
        proxy_set_header x-server $host;
        proxy_set_header x-agent $http_user_agent;
        proxy_pass http://app;
    }
}

[root@node132 conf.d]# ss -nltp|grep java
LISTEN    0  1    ::ffff:127.0.0.1:8005  :::*      users:(("java",39559,45))
LISTEN    0  100                :::8009  :::*      users:(("java",39559,43))
LISTEN    0  100                :::8080  :::*      users:(("java",39559,42))

tomcat版本
[root@node132 conf.d]# /usr/local/tomcat/bin/catalina.sh version
Using CATALINA_BASE:  /usr/local/tomcat
Using CATALINA_HOME:  /usr/local/tomcat
            ....
Server version: Apache Tomcat/7.0.69
Server built:  Apr 11 2016 07:57:09 UTC
Server number:  7.0.69.0
OS Name:        Linux
OS Version:    2.6.32-573.el6.x86_64
Architecture:  amd64
JVM Version:    1.7.0_79-b15
JVM Vendor:    Oracle Corporation

验证结果
# curl http://localhost

<!DOCTYPE html>

<html lang="en">
    <head>
        <title>Apache Tomcat/7.0.69</title>
        <link href="favicon.ico" rel="icon" type="image/x-icon" />
        <link href="favicon.ico" rel="shortcut icon" type="image/x-icon" />
        <link href="tomcat.css" rel="stylesheet" type="text/css" />
    </head>
    ......

五、proxy模块指令描述

proxy模块的可用配置指令非常多，它们分别用于定义proxy模块工作时的诸多属性，如连接超时时长、代理时使用http协议版本等。下面对常用的指令做一个简单说明。

proxy_connect_timeout
  nginx将一个请求发送至upstream server之前等待的最大时长；
proxy_cookie_domain
  将upstream server通过Set-Cookie首部设定的domain属性修改为指定的值，其值可以为一个字符串、正则表达式的模式或一个引用的变量；
proxy_cookie_path
   将upstream server通过Set-Cookie首部设定的path属性修改为指定的值，其值可以为一个字符串、正则表达式的模式或一个引用的变量；
proxy_hide_header
  设定发送给客户端的报文中需要隐藏的首部；
proxy_pass
  指定将请求代理至upstream server的URL路径；
proxy_set_header
  将发送至upsream server的报文的某首部进行重写；
proxy_redirect
  重写location并刷新从upstream server收到的报文的首部；
proxy_send_timeout
  在连接断开之前两次发送至upstream server的写操作的最大间隔时长；
proxy_read_timeout
   在连接断开之前两次从接收upstream server接收读操作的最大间隔时长；

如下面的一个示例：
    proxy_redirect off;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    client_max_body_size 10m;
    client_body_buffer_size 128k;
    proxy_connect_timeout 30;
    proxy_send_timeout 15;
    proxy_read_timeout 15;

注：最后更新时间20171110，添加反向代理至tomcat内容