How cluster module works in Node.js - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the cluster module in Node.js.

Node.js

const cluster = require('[1]');

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Anet

Bhttp

Cfs

Dcluster

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'http' instead of 'cluster' to import the cluster module.

Forgetting to use require() to import the module.

The cluster module is imported using require('cluster') in Node.js.

2fill in blank

medium

Complete the code to check if the current process is the master in a cluster.

Node.js

if (cluster.[1]) {
  console.log('This is the master process');
}

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AisPrimary

BisMaster

CisWorker

DisMain

Attempts:

3 left

💡 Hint

Common Mistakes

Using isMaster which is deprecated in newer Node.js versions.

Using isWorker which is the opposite of master.

In Node.js v16+, cluster.isPrimary is used to check if the process is the master (primary) process.

3fill in blank

hard

Fix the error in the code to fork a worker process.

Node.js

const worker = cluster.[1]();

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Aspawn

Bstart

Cfork

Dcreate

Attempts:

3 left

💡 Hint

Common Mistakes

Using start() which does not exist in cluster.

Using spawn() which is from child_process module, not cluster.

The correct method to create a new worker process in the cluster module is fork().

4fill in blank

hard

Fill both blanks to create a simple HTTP server in a worker process.

Node.js

if (cluster.isPrimary) {
  cluster.[1]();
} else {
  const http = require('http');
  http.createServer((req, res) => {
    res.writeHead(200);
    res.end(`Hello from worker ${cluster.worker.[2]`);
  }).listen(8000);
}

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Afork

BisMaster

Cid

DisWorker

Attempts:

3 left

💡 Hint

Common Mistakes

Using isMaster instead of fork() to create workers.

Using isWorker instead of id to identify workers.

The master process forks workers using cluster.fork(). Each worker has an id property used here to identify it.

5fill in blank

hard

Fill all three blanks to handle worker exit and restart a new worker.

Node.js

cluster.on('exit', (worker, code, signal) => {
  console.log(`Worker ${worker.[1] died with code ${code}`);
  console.log('Starting a new worker');
  cluster.{{BLANK_3}}();
});

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Aid

Bfork

Ccode

Dpid

Attempts:

3 left

💡 Hint

Common Mistakes

Using pid instead of id for worker identification.

Using signal instead of code for exit code.

Not calling fork() to restart a worker.

When a worker dies, its id and exit code are logged. Then a new worker is started with cluster.fork().