Mac环境下Nginx+Tomcat集群搭建

什么是Nginx？
Nginx是一个高性能的HTTP和反向代理服务器，也是一个IMAP POP3 SMTP 服务器。
在连接高并发的情况下，Nginx是Apache服务器不错的替代品：Nginx在美国是做虚拟主机生意的老板们经常选择的软件平台之一。能够支持高达 50,000 个并发连接数的响应，感谢Nginx为我们选择了 epoll and kqueue作为开发模型。
Nginx作为负载均衡服务器：Nginx 既可以在内部直接支持 Rails 和 PHP 程序对外进行服务，也可以支持作为 HTTP代理服务器对外进行服务。Nginx采用C进行编写，不论是系统资源开销还是CPU使用效率都比 Perlbal 要好很多。


第一步: 安装我们的Nginx, Mac上是利用brew安装的; 
brew install nginx  使用 nginx -v 查看安装的版本
安装的默认路径在 /usr/local/etc/nginx

使用 sudo nginx 启动nginx
出现这个问题: XXX   is not in the sudoers file.This incident will be reported.
参照 http://blog.163.com/chenchen..1986/blog/static/76063146201651842856320/ enable系统的root用户
然后:
1.切换到root用户下,sudo -i命令

2.添加sudo文件的写权限,命令是:
chmod u+w /etc/sudoers

3.编辑sudoers文件
vi /etc/sudoers
找到这行 root ALL=(ALL) ALL,在他下面添加xxx ALL=(ALL) ALL (这里的xxx是你的用户名)

ps:这里说下你可以sudoers添加下面四行中任意一条
youuser            ALL=(ALL)                ALL
%youuser           ALL=(ALL)                ALL
youuser            ALL=(ALL)                NOPASSWD: ALL
%youuser           ALL=(ALL)                NOPASSWD: ALL

第一行:允许用户youuser执行sudo命令(需要输入密码).
第二行:允许用户组youuser里面的用户执行sudo命令(需要输入密码).
第三行:允许用户youuser执行sudo命令,并且在执行的时候不输入密码.
第四行:允许用户组youuser里面的用户执行sudo命令,并且在执行的时候不输入密码.

4.撤销sudoers文件写权限,命令:
chmod u-w /etc/sudoers



使用 ps -ef|grep nginx 来查看nginx启动是否成功

第二步:
在本地启动两个tomcat.
需要将tomcat的端口分别更改：
<Server port="8105" shutdown="SHUTDOWN">
<Connector URIEncoding="UTF-8" connectionTimeout="20000" port="8180" protocol="HTTP/1.1" redirectPort="8443"/>
<Connector port="8109" protocol="AJP/1.3" redirectPort="8443"/>

<Server port="8205" shutdown="SHUTDOWN">
<Connector URIEncoding="UTF-8" connectionTimeout="20000" port="8280" protocol="HTTP/1.1" redirectPort="8443"/>
<Connector port="8209" protocol="AJP/1.3" redirectPort="8443"/>


第三步:
在 /usr/local/etc/nginx路径下更改 nginx.conf文件的内容


#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 localhost {
      #ip_hash; 
      server localhost:8180;
      server localhost:8280;
	}
    server {
        listen       80;
        server_name  localhost;

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
            root   html;
            index  index.html index.htm;
            proxy_pass  http://localhost;  
            proxy_set_header X-Real-IP $remote_addr; 
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; 
            proxy_redirect HOST default; 
        }

        #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;
    #    }
    #}
    include servers/*;
}


增加了:

upstream localhost {
      #ip_hash; 
      server localhost:8180;
      server localhost:8280;
}

 location / {
            root html;
            index index.html index.htm;
            proxy_pass  http://localhost;  
            proxy_set_header X-Real-IP $remote_addr; 
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; 
            proxy_redirect HOST default; 
        }


第四步测试: 访问localhost:8080  看到tomcat欢迎页面，配置成功

nginx分别连接到启动的两个tomcat server。
当你关闭一个tomcat-1,nginx访问仍然良好，当你关闭另一个tomcat-2，nginx无法访问。