nginx反向代理负载均衡功能

客户端====代理服务器===web服务器

反向代理功能架构
3台web服务器，组建出web服务器集群
web01  10.0.0.7   172.16.1.7
web02  10.0.0.8   172.16.1.8
web03  10.0.0.9   172.16.1.9
1台负载均衡服务器
lb01   10.0.0.5   172.16.1.5    

①. 部署web服务器
    第一个里程：安装部署nginx软件  注：另外两台web服务器也要部署相同的nginx服务
    mkdir /server/tools -p
    cd /server/tools
    wget http://nginx.org/download/nginx-1.12.2.tar.gz
    tar xf nginx-1.12.2.tar.gz
    yum install -y pcre-devel openssl-devel
    useradd -M -s /sbin/nologin www
    cd nginx-1.12.2
    ./configure --prefix=/application/nginx-1.12.2 --user=www --group=www --with-http_ssl_module --with-http_stub_status_module
    make && make install
    ln -s /application/nginx-1.12.2 /application/nginx
    /application/nginx/sbin/nginx
    netstat -lntup|grep nginx

   第二个里程：编辑nginx配置文件
   server {
       listen       80;
       server_name  www.etiantian.org;
       root   html/www;
       index  index.html index.htm;
   }
   server {
       listen       80;
       server_name  bbs.etiantian.org;
       root   html/bbs;
       index  index.html index.htm;
   }
   scp -rp /application/nginx/conf/nginx.conf 172.16.1.8:/application/nginx/conf/
   scp -rp /application/nginx/conf/nginx.conf 172.16.1.8:/application/nginx/conf/

   第三里程：创建模拟测试环境
   mkdir /application/nginx/html/{www,bbs} -p
   for name in www bbs;do echo "$(hostname) $name.etiantian.org" >/application/nginx/html/$name/oldboy.html;done
   for name in www bbs;do cat /application/nginx/html/$name/oldboy.html;done

   第四里程：在负载均衡服务器上，进行测试访问
   curl -H host:www.etiantian.org 10.0.0.7/oldboy.html
   web01 www.etiantian.org
   curl -H host:bbs.etiantian.org 10.0.0.7/oldboy.html
   web01 bbs.etiantian.org
   curl -H host:www.etiantian.org 10.0.0.8/oldboy.html
   web02 www.etiantian.org
   curl -H host:bbs.etiantian.org 10.0.0.8/oldboy.html
   web02 bbs.etiantian.org
   curl -H host:www.etiantian.org 10.0.0.9/oldboy.html
   web03 www.etiantian.org
   curl -H host:bbs.etiantian.org 10.0.0.9/oldboy.html
   web03 bbs.etiantian.org

②. 部署负载均衡服务器
    第一个里程：安装部署nginx软件
    mkdir /server/tools -p
    cd /server/tools
    wget http://nginx.org/download/nginx-1.12.2.tar.gz
    tar xf nginx-1.12.2.tar.gz
    yum install -y pcre-devel openssl-devel
    useradd -M -s /sbin/nologin www
    cd nginx-1.12.2
    ./configure --prefix=/application/nginx-1.12.2 --user=www --group=www --with-http_ssl_module --with-http_stub_status_module
    make && make install
    ln -s /application/nginx-1.12.2 /application/nginx
    /application/nginx/sbin/nginx
    netstat -lntup|grep nginx

    第二个里程：编写nginx反向代理配置文件
    grep -Ev "#|^$" nginx.conf.default >nginx.conf

    官方链接：http://nginx.org/en/docs/http/ngx_http_upstream_module.html#upstream
    Syntax: upstream name { ... }
    Default:    —
    Context:    http
    eg：
    upstream oldboy {
       server 10.0.0.7:80;
       server 10.0.0.8:80;
       server 10.0.0.9:80;
    }
    说明：upstream模块就类似定一个一个地址池或者说定一个web服务器组

    官方链接：http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_pass
    Syntax: proxy_pass URL;
    Default:    —
    Context:    location, if in location, limit_except
    eg：
    location / {
       proxy_pass http://oldboy;
    }
    说明：proxy_pass主要用于进行抛送用户访问请求给upstream模块中的相应节点服务器

    worker_processes  1;
    events {
        worker_connections  1024;
    }
    http {
        include       mime.types;
        default_type  application/octet-stream;
        sendfile        on;
        keepalive_timeout  65;
        upstream oldboy {
            server 10.0.0.7:80;
            server 10.0.0.8:80;
            server 10.0.0.9:80;
        }
        server {
            listen       80;
            server_name  localhost;
            root   html;
            index  index.html index.htm;
          location / {
            proxy_pass http://oldboy;
           }   
        }
    }

    /application/nginx/sbin/nginx -t
    /application/nginx/sbin/nginx -s reload

    第三个里程：进行访问负载均衡服务器测试
    1）利用浏览器进行测试
       进行hosts解析
       http://www.etiantian.org/oldboy.html  <--利用ctrl+F5刷新测试，检查是否进行负载调度
    2）利用curl命令进行测试
       [root@lb01 conf]# curl -H host:www.etiantian.org 10.0.0.5/oldboy.html
       web01 www.etiantian.org
       [root@lb01 conf]# curl -H host:www.etiantian.org 10.0.0.5/oldboy.html
       web02 www.etiantian.org
       [root@lb01 conf]# curl -H host:www.etiantian.org 10.0.0.5/oldboy.html
       web03 www.etiantian.org