基于树状的负载在应用层解决高并发问题，nginx做代理服务器进行负载均衡，场景如下：

1.本机模拟，模拟成3台

2.前置机为nginx，端口为80

3.应用服务器端口分别为8082和8083都以nginx进行模拟

4.nginx版本为：nginx-1.6.2

应用服务器1配置：

#user  nobody;worker_processes  1;events {    worker_connections  1024;}http {    include       mime.types;    default_type  application/octet-stream;    sendfile        on;     keepalive_timeout  65;    server {        listen       8083;        server_name  localhost;         location / {            root   html;            index  index.html index.htm;        }        error_page   500 502 503 504  /50x.html;        location = /50x.html {            root   html;        }       }}

应用服务器2配置：

#user  nobody;worker_processes  1;events {    worker_connections  1024;}http {    include       mime.types;    default_type  application/octet-stream;    sendfile        on;     keepalive_timeout  65;    server {        listen       8082;        server_name  localhost;         location / {            root   html;            index  index.html index.htm;        }        error_page   500 502 503 504  /50x.html;        location = /50x.html {            root   html;        }       }}

前置机配置：

#user  nobody;worker_processes  1;events {    worker_connections  1024;}http {    include       mime.types;    default_type  application/octet-stream;    sendfile        on;    keepalive_timeout  65;    upstream  linkrmb.com {          server  127.0.0.1:8083;          server  127.0.0.1:8082;    }     server {        listen       80;        server_name  localhost;         location / {            proxy_pass         http://linkrmb.com;             proxy_set_header   Host             $host;             proxy_set_header   X-Real-IP        $remote_addr;             proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;         }            error_page   500 502 503 504  /50x.html;        location = /50x.html {            root   html;        }    }}

前置机的代理配置主要点：

1.设置upstream

2.设置proxy_pass

默认的转发策略为轮询