Using PM2 for Process Management and Clustering

1. Introduction

In this tutorial, we will be exploring PM2, a powerful process manager for Node.js applications. PM2 assists in managing application services, maintaining application states, and setting up clustering efficiently. By the end of this tutorial, you will understand how to use PM2 for managing your Node.js applications.

What You Will Learn
- What is PM2
- How to install and use PM2
- How to use PM2 for process management and clustering

Prerequisites
- Basic knowledge of Node.js
- Node.js and NPM installed in your local system

2. Step-by-Step Guide

What is PM2?

PM2 stands for Process Manager 2. It's a production process manager for Node.js applications with a built-in load balancer. It allows you to keep applications alive forever, reloads them without downtime, helps in managing application logging, monitoring, and clustering.

Installation

To install PM2, use the following NPM command:

npm install pm2 -g

Starting an Application

To start an application with PM2, navigate to your application directory and use the following command:

pm2 start app.js

3. Code Examples

Listing All Processes

To list all running processes, use the following command:

pm2 list

Monitoring Applications

PM2 provides a handy dashboard to monitor the CPU and memory usage of your applications.

pm2 monit

Application Clustering

PM2 allows you to run applications in cluster mode without any code modifications. This is useful for taking full advantage of multi-core systems.

pm2 start app.js -i max

In this command, -i max will start as many instances as possible based on the number of CPU cores available.

4. Summary

Throughout this tutorial, we've learned about PM2, how to install it, and its basic usage. We've discussed some of the essential features of PM2 like process listing, application monitoring, and clustering.

To learn more about PM2 and its advanced features, you can refer to the official PM2 documentation.

5. Practice Exercises

1. Exercise 1: Start, list, and stop a simple Node.js application using PM2.

Solution: Start the application using pm2 start app.js, list all processes using pm2 list, and stop the application using pm2 stop app.js.

1. Exercise 2: Use PM2 to monitor the CPU and memory usage of your application.

Solution: Start your application using PM2 and use the pm2 monit command to monitor the application.

1. Exercise 3: Start a Node.js application in cluster mode using PM2.

Solution: Use the command pm2 start app.js -i max to start the application in cluster mode.

Keep practicing and exploring the different features of PM2. It's a powerful tool that can greatly simplify the management and deployment of your Node.js applications.