Nginx是如何实现七层的负载均衡的

下文给大家带来Nginx是如何实现七层的负载均衡的，希望能够给大家在实际运用中带来一定的帮助，负载均衡涉及的东西比较多，理论也不多，网上有很多书籍，今天我们就用亿速云在行业内累计的经验来做一个解答。

Nginx实现七层的负载均衡

调度到不同组后端云服务器
1. 动静分离
2. 网站进行分区
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拓扑结构

                [vip: 20.20.20.20]

            [LB1 Nginx]      [LB2 Nginx]
            192.168.1.2       192.168.1.3

[index]      [milis]     [videos]     [p_w_picpaths]      [news]
1.11         1.21         1.31         1.41         1.51
1.12          1.22         1.32         1.42         1.52
1.13          1.23         1.33         1.43         1.53
...            ...          ...          ...          ...
/web       /web/milis    /web/videos   /web/p_w_picpaths   /web/news
index.html   index.html   index.html                 index.html


一、实施过程
方案一　根据站点分区进行调度
http {
   upstream index {
       server 192.168.1.11:80 weight=1 max_fails=2 fail_timeout=2;
       server 192.168.1.12:80 weight=2 max_fails=2 fail_timeout=2;
       server 192.168.1.13:80 weight=2 max_fails=2 fail_timeout=2;
      }
     
   upstream milis {
       server 192.168.1.21:80 weight=1 max_fails=2 fail_timeout=2;
       server 192.168.1.22:80 weight=2 max_fails=2 fail_timeout=2;
       server 192.168.1.23:80 weight=2 max_fails=2 fail_timeout=2;
      }
     
    upstream videos {
       server 192.168.1.31:80 weight=1 max_fails=2 fail_timeout=2;
       server 192.168.1.32:80 weight=2 max_fails=2 fail_timeout=2;
       server 192.168.1.33:80 weight=2 max_fails=2 fail_timeout=2;
      }
     
    upstream p_w_picpaths {
       server 192.168.1.41:80 weight=1 max_fails=2 fail_timeout=2;
       server 192.168.1.42:80 weight=2 max_fails=2 fail_timeout=2;
       server 192.168.1.43:80 weight=2 max_fails=2 fail_timeout=2;
      }
     
     upstream news {
       server 192.168.1.51:80 weight=1 max_fails=2 fail_timeout=2;
       server 192.168.1.52:80 weight=2 max_fails=2 fail_timeout=2;
       server 192.168.1.53:80 weight=2 max_fails=2 fail_timeout=2;
      }
     
    server {
          location / {
      proxy_pass http://index;
      }
     
      location  /news {
      proxy_pass http://news;
      }
     
      location /milis {
      proxy_pass http://milis;
      }
     
      location ~* \.(wmv|mp4|rmvb)$ {
      proxy_pass http://videos;
      }
     
      location ~* \.(png|gif|jpg)$ {
      proxy_pass http://p_w_picpaths;
      }
}


方案二 根据动静分离进行调度
http {
    upstream htmlservers {
       server 192.168.1.1:80 weight=1 max_fails=2 fail_timeout=2;
       server 192.168.1.2:80 weight=2 max_fails=2 fail_timeout=2;
        }
       
upstream phpservers {
       server 192.168.1.3:80 weight=1 max_fails=2 fail_timeout=2;
       server 192.168.1.4:80 weight=2 max_fails=2 fail_timeout=2;
        }
       
     server {
      location ~* \.html$ {
      proxy_pass http://htmlservers;
      }
     
      location ~* \.php$ {
      proxy_pass http://phpservers;
      }
     }
}


二、Keepalived实现调度器HA
注：主/备调度器均能够实现正常调度
1. 主/备调度器安装软件
[root@master ~]# yum -y install keepalived
[root@backup ~]# yum -y install keepalived

2. Keepalived
BACKUP1
[root@uplook ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
  router_id director1 //辅助改为director2
}

vrrp_instance VI_1 {
   state BACKUP
   nopreempt    
   interface eth0 //心跳接口，尽量单独连接心跳
   virtual_router_id 80//整个集群的调度器一致
   priority 100 //辅助改为50
   advert_int 1
   authentication {
       auth_type PASS
       auth_pass 1111
   }
   virtual_ipaddress {
       20.20.20.20
   }
}

BACKUP2


3. 启动KeepAlived（主备均启动）
[root@uplook ~]# chkconfig keepalived on
[root@uplook ~]# service keepalived start
[root@uplook ~]# ip addr

到此：
可以解决心跳故障keepalived
不能解决Nginx服务故障

4. 扩展对调度器Nginx健康检查（可选）
思路：
让Keepalived以一定时间间隔执行一个外部脚本，脚本的功能是当Nginx失败，则关闭本机的Keepalived
a. script
[root@master ~]# cat /etc/keepalived/check_nginx_status.sh
#!/bin/bash
/usr/bin/curl -I http://localhost &>/dev/null
if [ $? -ne 0 ];then
/etc/init.d/keepalived stop
fi
[root@master ~]# chmod a+x /etc/keepalived/check_nginx_status.sh

b. keepalived使用script
! Configuration File for keepalived

global_defs {
  router_id director1
}

vrrp_script check_nginx {
  script "/etc/keepalived/check_nginx_status.sh"
  interval 5
}

vrrp_instance VI_1 {
   state BACKUP
   interface eth0
   nopreempt
   virtual_router_id 90
   priority 100
   advert_int 1
   authentication {
       auth_type PASS
       auth_pass uplook
   }
   
   virtual_ipaddress {
       192.168.1.80
   }

   track_script {
       check_nginx
   }
}

注：必须先启动nginx，再启动keepalived




     调度到同一组后端服务器
网站没按业务/版块拆分，所有后端服务器提供整站代码。
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拓扑结构

              [LB Nginx]
              20.20.20.20
              192.168.1.2

[httpd]         [httpd]      [httpd]
192.168.1.3    192.168.1.4    192.168.1.5


实施过程
1. nginx
http {
   upstream httpservers {
       server 192.168.1.3:80 weight=1 max_fails=2 fail_timeout=2;
       server 192.168.1.4:80 weight=2 max_fails=2 fail_timeout=2;
       server 192.168.1.5:80 weight=2 max_fails=2 fail_timeout=2;
       server 192.168.1.100:80 backup;         等3、4、5 挂掉100上线
   }

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

2. Apache LogFormat 可选
LogFormat "%{X-Real-IP}i %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %b" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent

3. Nginx LogFormat

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