NGINX系列教材 （五）- 和TOMCAT进行负载均衡ZHENG'HE

步骤 1 : 负载均衡的概念
负载均衡的概念就是当访问量很大的时候，一个 Tomcat 吃不消了，这时候就准备多个 Tomcat，由Nginx按照权重来对请求进行分配，从而缓解单独一个Tomcat受到的压力

步骤 2 : 启动两个Tomcat
到多个Tomcat下载解压8111和8222两个tomcat，并启动

步骤 3 : 修改nginx.conf
首先增加一个upstream ，用来指向这两个tomcat

upstream tomcat_8111_8222{
server	127.0.0.1:8111 weight=1;
server	127.0.0.1:8222 weight=2;
}

然后修改location，反向代理到上述配置。

    location / {
    	proxy_pass http://tomcat_8111_8222;
}

weight表示权重，值越大，被分配到的几率越大。 最大多少呢？我也不知道。。。反正10以内都可以用吧

#user  nobody;
worker_processes  1;
 
#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;
 
#pid        logs/nginx.pid;
 
events {
    worker_connections  1024;
}
 
http {
    include       mime.types;
    default_type  application/octet-stream;
 
    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';
 
    #access_log  logs/access.log  main;
 
    sendfile        on;
    #tcp_nopush     on;
 
    #keepalive_timeout  0;
    keepalive_timeout  65;
 
    #gzip  on;
 
    upstream tomcat_8111_8222{
    server  127.0.0.1:8111  weight=1;
    server  127.0.0.1:8222 weight=2;
    }
 
    server {
        listen       80;
        server_name  localhost;
 
        #charset koi8-r;
 
        #access_log  logs/host.access.log  main;
 
        location / {
            proxy_pass http://tomcat_8111_8222;
    }
 
        location ~\.(css|js|png)$ {
            root C:/Users/X7TI/Downloads/tomcat_8111/webapps/ROOT;
    }
 
        #error_page  404              /404.html;
 
        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
 
        # proxy the PHP scripts to Apache listening on 127.0.0.1:80
        #
        #location ~ \.php$ {
        #    proxy_pass   http://127.0.0.1;
        #}
 
        # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        #location ~ \.php$ {
        #    root           html;
        #    fastcgi_pass   127.0.0.1:9000;
        #    fastcgi_index  index.php;
        #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
        #    include        fastcgi_params;
        #}
 
        # deny access to .htaccess files, if Apache's document root
        # concurs with nginx's one
        #
        #location ~ /\.ht {
        #    deny  all;
        #}
    }
 
    # another virtual host using mix of IP-, name-, and port-based configuration
    #
    #server {
    #    listen       8000;
    #    listen       somename:8080;
    #    server_name  somename  alias  another.alias;
 
    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}
 
    # HTTPS server
    #
    #server {
    #    listen       443 ssl;
    #    server_name  localhost;
 
    #    ssl_certificate      cert.pem;
    #    ssl_certificate_key  cert.key;
 
    #    ssl_session_cache    shared:SSL:1m;
    #    ssl_session_timeout  5m;
 
    #    ssl_ciphers  HIGH:!aNULL:!MD5;
    #    ssl_prefer_server_ciphers  on;
 
    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}
 
}

步骤 4 : 重启nginx并访问
使用命令 nginx -s reload 重启，然后使劲访问

http://127.0.0.1/login.jsp

此时就可以观察到对jsp的访问，被分配到了不同的 Tomcat上