multiple-ports.js

var cluster = require('cluster')
  , express = require('express')
  , config = require('./config/config');

if (cluster.isMaster) {
  for (var i = 0; i < config.ports.length; i++) {
    cluster.fork({ PORT: config.ports[i] });
  }
} else {
  var app = express();
  app.listen(process.env.PORT);
  console.log('Listening port ' + process.env.PORT + '...');
}