Node.js

Cluster Process

Module

❮ Built-in Modules

Example

Run the code three times, the first time is as a master, then as workers:

var cluster = require(‘cluster’);

if (cluster.isWorker) {
 
console.log(‘I am a worker’);
} else {
  console.log(‘I am a
master’);
  cluster.fork();
  cluster.fork();
}

Run example »

Run the code three times, the first time is as a master, then as workers:

Definition and Usage

The cluster module provides a way of creating child processes that runs
simultaneously and share the same server port.

Node.js runs single threaded programming, which is very memory efficient, but
to take advantage of computers multi-core systems, the Cluster module allows you
to easily create child processes that each runs on their own single thread, to
handle the load.

Syntax

The syntax for including the cluster module in your application:

var cluster = require(‘cluster’);

Cluster Properties and Methods

Method
Description

disconnect()
Disconnects all workers

exitedAfterDisconnect
Returns true if a worker was exited after disconnect, or the kill method

fork()
Creates a new worker, from a master

id
A unique id for a worker

isConnected
Returns true if the worker is connected to its
master, otherwise false

isDead
Returns true if the worker’s process is dead,
otherwise false

isMaster
Returns true if the current process is master,
otherwise false

isWorker
Returns true if the current process is worker,
otherwise false

kill()
Kills the current worker

process
Returns the global Child Process

schedulingPolicy
Sets or gets the schedulingPolicy

send()
sends a message to a master or a worker

settings
Returns an object containing the cluster’s settings

setupMaster()
Changes the settings of a cluster

worker
Returns the current worker object

workers
Returns all workers of a master

❮ Built-in Modules