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

1. Process Management: PM2 helps manage and monitor Node.js applications, ensuring they run continuously.
2. Load Balancing: PM2 can distribute incoming traffic across multiple instances of your application.
3. Monitoring: PM2 provides real-time monitoring and logging of your applications.
4. Deployment: PM2 simplifies the deployment process with built-in support for various deployment strategies.

To install PM2 globally on your system, use the following command:

To start a Node.js application with PM2, use the start command:

To list all running processes managed by PM2, use:

To stop a specific application, use the stop command followed by the process ID or name:

To restart an application, use the restart command:

To delete a process from PM2's list, use the delete command:

Let's create a simple Node.js application and manage it with PM2.

Create a file named app.js with the following content:

Start the application using PM2:

List the running processes to see your application:

You should see an output similar to this:

Stop the application using PM2:

Restart the application using PM2:

Delete the application from PM2's list:

PM2 can run multiple instances of your application to handle more traffic. Use the -i option to specify the number of instances:

PM2 provides real-time monitoring and logging. Use the following commands to access these features:

• Monitor: pm2 monit
• Logs: pm2 logs

PM2 can automatically restart your application when it detects file changes. Use the --watch option:

1. Create a simple Node.js application that responds with "Hello, PM2!".
2. Start the application using PM2.
3. Monitor the application using PM2.
4. Stop and restart the application using PM2.
5. Enable auto-restart on file changes.

1. Create a file named app.js with the following content:

   const http = require('http');
   
   const server = http.createServer((req, res) => {
     res.writeHead(200, { 'Content-Type': 'text/plain' });
     res.end('Hello, PM2!\n');
   });
   
   server.listen(3000, () => {
     console.log('Server running at http://localhost:3000/');
   });
   

2. Start the application using PM2:

   pm2 start app.js
   

3. Monitor the application using PM2:

   pm2 monit
   

4. Stop and restart the application using PM2:

   pm2 stop app.js
   pm2 restart app.js
   

5. Enable auto-restart on file changes:

   pm2 start app.js --watch
   

In this section, you learned how to use PM2 for process management in Node.js applications. You covered installation, starting, stopping, restarting, and deleting processes, as well as advanced features like load balancing, monitoring, and auto-restart on file changes. These skills will help you manage and monitor your Node.js applications effectively, ensuring they run smoothly in production environments.