Node.js PM2

Introduction to PM2

PM2 is a popular process manager for Node.js applications. It is designed to keep your applications alive forever, reload them without downtime, and facilitate common system admin tasks.

With PM2, you can easily manage multiple Node.js applications, achieve zero downtime reloads, and monitor your applications in real-time. This makes it an essential tool for deploying Node.js applications.

Installing PM2

Installing PM2 is straightforward. You can install it globally using npm, the Node.js package manager. Here's the command you need to execute:

Starting an Application with PM2

Once PM2 is installed, you can start your Node.js application using the following command. This will start your application and automatically manage it with PM2.

Managing Applications

PM2 offers several commands to manage applications efficiently:

• List Applications: Use the pm2 list command to see all running applications managed by PM2.
• Stop an Application: Stop an application with pm2 stop <app_name|id>.
• Restart an Application: Restart any application using pm2 restart <app_name|id>.
• Delete an Application: Remove an application from PM2's list with pm2 delete <app_name|id>.

Clustering with PM2

One of PM2's powerful features is clustering, which allows you to take advantage of multi-core systems. By using the --instances parameter, you can start your application in cluster mode, enabling it to run multiple instances across different CPU cores.

Monitoring Applications

PM2 provides built-in monitoring features that allow you to keep track of your application's performance in real-time. Use the pm2 monit command to access the monitoring dashboard.

Conclusion

PM2 is a robust tool that simplifies the process management of Node.js applications. With its features like clustering, monitoring, and zero-downtime reloads, it is an indispensable tool for any Node.js developer. In the next post, we'll explore Docker and how it complements tools like PM2 in deployment pipelines.