assign separate server/port to each worker?

nodejs_cluster.js

const cluster = require('cluster');
const http = require('http');
const numCPUs = require('os').cpus().length;

if (cluster.isMaster) {
  console.log(`Master ${process.pid} is running`);
   var worker_id = '';
  // Fork workers.
  for (let i = 0; i < numCPUs; i++) {
    worker_id = '900'+i;
    cluster.fork({port : worker_id});
    
  }

  cluster.on('exit', (worker, code, signal) => {
    console.log(`worker ${worker.process.pid} died`);
  });
} else {
  console.log("App listening in ", process.env.port)
  // Workers can share any TCP connection
  // In this case it is an HTTP server
  http.createServer((req, res) => {
    res.writeHead(200);
    res.end('hello world\n');
  }).listen(process.env.port);

  console.log(`Worker ${process.pid} started`);
}