cluster

var cluster = requre('custer');

var http = require('http');

var numCPUs = require('os').cpus().length;

if(cluster.isMaster){

　　// fork workers

　　for(var i=0;i<numCPUs;i++){

　　　　cluster.fork();

　　}

　　cluster.on('exit', function(worker, code, singal){

　　　　console.log('worker'+worker.process.pid+''died');

　　});

} else {

　　// worker can share any tcp connection

　　http.createServer(function(req, res){

　　　　rs.writeHead(200);

　　　　rs.end('hello');

　　}).listen(200);

}

cluster.isWorker =('NODE_UNIQUE_ID' in process.env)

cluster.isMaster = (cluster.isWorker === false);