hydraserver.js

var http = require('http'),
    cluster = require('cluster')

function hydraServer(requestListener, heads){
  var server,
      i;
  if(cluster.isMaster) {
    for(i = 0; i < heads; i++) {
      cluster.fork()
    } 
  } else {
    http.createServer(requestListener).listen(3000) 
  }
}


var counter = 0;

hydraServer(function(req, res) {
  res.writeHead(
    200, {
    'Content-Type': 'text/plain'
  })
  counter++;
  res.end(''+counter)
}, 4)


/*

  Each time i hit the server it increments two times, 1, 3, 5, 7 and so forth.
  Why is the server firing the the requestListener two times?

*/