注意：
(1) 做负载均衡技术至少需要三台服务器：一台独立的负载均衡器，两台web服务器做集群

一、nginx分别代理后端web1 和 web2的三台虚拟主机

1、web1（nginx-10.0.0.7）配置基于端口的虚拟主机

[root@Oldboy extra]# cat www.conf 
server {
        listen        10.0.0.7:80;
#     server_name  www.etiantian.org;
        location / {
            root   html/www;
            index  index.html index.htm;
        }
        access_log  logs/www_access.log  main;
}
[root@Oldboy extra]# cat bbs.conf 
server {
        listen       10.0.0.7:8080;
#     server_name  bbs.etiantian.org;
        location / {
            root   html/bbs;
            index  index.php  index.html index.htm;
        }
        access_log  logs/bbs_access.log  main;
}
[root@Oldboy extra]# cat blog.conf           动态页面
server {
        listen       10.0.0.7:8081;
#      server_name  blog.etiantian.org;
        location / {
        root     html/blog;
        index    index.php;
}

        location ~ .*\.(php|php5)?$ {
        root html/blog;
        fastcgi_pass  127.0.0.1:9000;
        fastcgi_index index.php;
        include fastcgi.conf;
        }
        access_log  logs/blog_access.log  main;
}

2、web2（apache-10.0.0.8）配置基于端口的虚拟主机

NameVirtualHost 10.0.0.8:80
Listen 8080                                           手动写上监听端口，80在主配置文件
Listen 8081
<VirtualHost *:80>
    ServerAdmin oldboy@oldboyedu.com
    DocumentRoot "/application/apache2.2.31/htdocs/www"
    ServerAlias etiantian.org
    ErrorLog "/app/logs/www-error_log"
    CustomLog "/app/logs/www-access_log" common
</VirtualHost>

<VirtualHost 10.0.0.8:8080>
    ServerAdmin oldboy@oldboyedu.com
    DocumentRoot "/application/apache2.2.31/htdocs/bbs"
    ErrorLog "/app/logs/bbs-error_log"
    CustomLog "/app/logs/bbs-access_log" common
</VirtualHost>

<VirtualHost 10.0.0.8:8081>                                                            动态页面
    ServerAdmin oldboy@oldboyedu.com
    DocumentRoot "/application/apache2.2.31/htdocs/blog"
    ErrorLog "/app/logs/blog-error_log"
    CustomLog "/app/logs/blog-access_log" common
</VirtualHost>

3、负载均衡器（LB-nginx-10.0.0.6）配置反向代理

[root@Oldboy conf]# cat nginx.conf
worker_processes  1;
events {
    worker_connections  1024;
}
http {
    include       mime.types;
    default_type  application/octet-stream;
    sendfile        on;
    keepalive_timeout  65;

 upstream www_pool {                                                   www静态地址池
    server 10.0.0.7:80  weight=1;                                      权重越大优先级越高
    server 10.0.0.8:80  weight=1;
}

 upstream bbs_pool {                                                    bbs静态地址池
    server 10.0.0.7:8080  weight=1;
    server 10.0.0.8:8080  weight=1;
}

 upstream blog_pool {                                                  blog动态地址池
    server 10.0.0.7:8081  weight=1;
    server 10.0.0.8:8081  weight=1;
}



server {
        listen       80;
        server_name  www.etiantian.org;
        location / {
            index  index.html index.htm;
            proxy_pass http://www_pool;                                          代理www静态页面
            include proxy.conf;
        }
    }


server {
        listen       80;
        server_name  bbs.etiantian.org;
        location / {
            index  index.html index.htm;
            proxy_pass http://bbs_pool;                                            代理bbs静态页面
            include proxy.conf;
        }
    }

server {
        listen       80;
        server_name  blog.etiantian.org;
        location / {
            index  index.html index.htm;
            proxy_pass http://blog_pool;                                          代理blog动态页面
            include proxy.conf;
        }
    }
}

4、修改web端日志访问ip

默认情况下web端日志记录的访问ip是负载均衡器的ip，所以需要修改为真实客户端ip
(1) 负载均衡器（LB）配置
server {
        listen       80;
        server_name  blog.etiantian.org;
        location / {
            index  index.html index.htm;
            proxy_pass http://blog_pool;                                          代理blog动态页面
            proxy_set_header Host  $host;                                        
            proxy_set_header X-Forwarded-For $remote_addr;      负载均衡器开启ip转发，将客户端ip映射到web服务器
        }
    }
    (2) web1端修改（nginx主配置文件）
cat  nginx.conf

log_format  main  '$http_x_forwarded_for  $remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent"';

(3) web2端修改 （apache主配置文件）
LogFormat "%{X-Forwarded-For}i %h %l %u %t \"%r\" %>s %b"  common