cluster restart

restart.js

var cluster = require("cluster");

cluster.restart = function (callback) {
  
  var oldWorkers = [];
  cluster.eachWorker(function (worker) {
    oldWorkers.push(worker);
  });
  
  function restartWorker (oldWorker) {
    worker.on('disconnect', function () {
      var newWorker = worker.fork();
      newWorker.on('listening', function () {
        if (oldWorkers.length === 0) {
          callback && callback();
        } else {
          restartWorker(oldWorker.pop());
        }
      });
    });
    worker.disconnect();
  }
  restartWorker(oldWorker.pop());
  
};