《用Nginx做NodeJS应用的负载均衡》

作者：chszs，转载需注明。博客主页：http://blog.csdn.net/chszs

负载均衡可以把用户的请求分摊到多个服务器上进行处理，从而实现了对海量用户的访问支持。负载均衡的架构如图所示：

对于复杂的Web应用来说，用Nginx做前端负载均衡是理所当然的事。

下面，我们用Nginx做NodeJS应用的负载均衡。

1、配置Nginx

修改nginx.conf：

....
        upstream sample {
	      server 127.0.0.1:3000;
	      server 127.0.0.1:3001;
	      keepalive 64;
	    }
         server {
	        listen 80;
	        ....
            server_name 127.0.0.1;
	        ....
            location / {
               proxy_redirect off;
               proxy_set_header X-Real-IP $remote_addr;
               proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
               proxy_set_header X-Forwarded-Proto $scheme;
               proxy_set_header Host $http_host;
               proxy_set_header X-NginX-Proxy true;
               proxy_set_header Connection "";
               proxy_http_version 1.1;
               proxy_pass http://sample;
           }
        }

2、构建NodeJS服务器

var http = require('http');
var morgan       = require('morgan');

var server1 = http.createServer(function (req, res) {
  console.log("Request for:  " + req.url + "-- port 3000 ");
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello Node.js\n');
}).listen(3000, "127.0.0.1");

var server2 = http.createServer(function (req, res) {
  console.log("Request for:  " + req.url + "-- port 3001 ");
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello Node.js\n');
}).listen(3001, "127.0.0.1");

server1.once('listening', function() {
  console.log('Server running at http://127.0.0.1:3000/');
});

server2.once('listening', function() {
  console.log('Server running at http://127.0.0.1:3001/');
});

现在我们可以访问http://127.0.0.1

可以看到如下的输出：

  Server running at http://127.0.0.1:3000/
  Server running at http://127.0.0.1:3001/
  Request for:  /-- port 3001 
  Request for:  /favicon.ico-- port 3000 
  Request for:  /favicon.ico-- port 3001 
  Request for:  /-- port 3000 
  Request for:  /favicon.ico-- port 3001 
  Request for:  /favicon.ico-- port 3000 
  Request for:  /-- port 3001 
  Request for:  /favicon.ico-- port 3000 
  Request for:  /favicon.ico-- port 3001 
  Request for:  /-- port 3000 
  Request for:  /favicon.ico-- port 3001 
  Request for:  /favicon.ico-- port 3000