用Nginx做NodeJS应用的负载均衡
《用Nginx做NodeJS应用的负载均衡》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;
[*] }
[*] }
这里在3000端口和3001端口各有一个Node.js服务器，这两个服务器在做同样的工作。在upstream节，配置了两个Node.js服务器。此外，我们还设置了proxy_pass http://sample做HTTP请求代理。
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/');
[*]});
3、访问Nginx服务器
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
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