Mastering Process Management on Ubuntu Server: A Comprehensive Guide to Installing and Using PM2

In the world of server management, ensuring your Node.js applications run smoothly and reliably is paramount. That’s where PM2, the production process manager for Node.js applications, comes into play. It simplifies deployment, monitoring, and management, allowing you to focus on building great applications.

This comprehensive guide will walk you through the process of installing PM2 on your Ubuntu server and demonstrate how to leverage its powerful features for optimal performance and uptime.

Why Choose PM2?

Before we dive into the installation process, let’s understand why PM2 is a valuable tool for your Ubuntu server:

• Process Management: PM2 ensures your Node.js applications are always running, automatically restarting them in case of crashes or unexpected errors.
• Load Balancing: PM2’s built-in load balancer allows you to easily scale your application across multiple CPU cores, improving performance and responsiveness.
• Easy Deployment: PM2 simplifies the deployment process with features like zero-downtime restarts and remote deployment capabilities.
• Monitoring and Logging: PM2 provides real-time monitoring of your application’s resource usage, logs, and error reports, helping you identify and resolve issues quickly.
• Startup Script Generation: PM2 can generate startup scripts to automatically launch your applications upon server reboot, ensuring consistent uptime.

Prerequisites:

Before proceeding with the installation, ensure you have the following prerequisites:

• An Ubuntu Server: A running Ubuntu server (18.04, 20.04, or later recommended).
• Node.js and npm: Node.js and npm (Node Package Manager) should be installed on your server. If not, you can install them using the following commands:

bash
sudo apt update
sudo apt install nodejs npm

You can verify the installation by checking their versions:

bash
node -v
npm -v

• Sudo Privileges: You need a user account with sudo privileges to install software.

Step-by-Step Installation Guide:

Now, let’s get down to the installation process:

1. Install PM2 Globally using npm:

The easiest way to install PM2 is using npm. Open your terminal and run the following command:

bash
sudo npm install -g pm2

This command will install PM2 globally on your system, making it accessible from any directory.

2. Verify the Installation:

After the installation is complete, verify that PM2 is installed correctly by checking its version:

bash
pm2 -v

This should display the version number of the PM2 installation. If you see a version number, congratulations! PM2 is installed and ready to use.

3. Managing Your Node.js Application with PM2:

Now that PM2 is installed, let’s learn how to use it to manage your Node.js application:

• Starting Your Application: Navigate to the directory containing your Node.js application and start it using the following command:

bash
pm2 start app.js # Replace app.js with your application's entry point

This command starts your application in the background and adds it to PM2’s process list. PM2 will automatically restart the application if it crashes.

• Listing Processes: To see the list of processes managed by PM2, run:

bash
pm2 list

This command displays a table with information about each process, including its name, ID, status, CPU usage, memory usage, and uptime.

• Stopping and Restarting Applications: You can stop and restart applications using their name or ID:

bash
pm2 stop <app_name_or_id> # Stop the application
pm2 restart <app_name_or_id> # Restart the application

For example:

bash
pm2 stop my-app
pm2 restart 0 # Assuming 'my-app' has ID 0

• Deleting Applications: To remove an application from PM2’s process list, use the delete command:

bash
pm2 delete <app_name_or_id>

• Monitoring Application Logs: PM2 allows you to easily view the logs of your applications:

bash
pm2 logs <app_name_or_id>

This command displays the real-time logs of the specified application in your terminal. You can also use pm2 monit for a more visual monitoring interface.

4. Enabling Startup on Boot:

To ensure your applications are automatically started when the server reboots, you need to generate a startup script:

bash
pm2 startup systemd

This command detects your operating system and generates the appropriate startup script. Follow the instructions displayed on the terminal to execute the command that configures the script. It usually looks something like this:

bash
sudo env PATH=$PATH:/usr/bin /usr/lib/node_modules/pm2/bin/pm2 startup systemd -u <your_username> --hp /home/<your_username>

Replace <your_username> with your actual username. After running this command, save the current process list using:

bash
pm2 save

This command saves the list of currently running applications so that they are automatically restarted upon server reboot.

5. Advanced PM2 Features:

PM2 offers a range of advanced features to enhance your application management:

• Clustering: PM2 can automatically cluster your Node.js application across multiple CPU cores to improve performance. To enable clustering, use the -i flag with the start command:

bash
pm2 start app.js -i max # Use the maximum number of CPU cores
pm2 start app.js -i 4 # Use 4 CPU cores

• Ecosystem Files: Ecosystem files are configuration files that define how PM2 should manage your applications. They allow you to specify various options, such as environment variables, restart policies, and deployment settings. Create an ecosystem file named ecosystem.config.js or ecosystem.config.json in your application directory and define your configurations. Here’s an example ecosystem.config.js:

javascript
module.exports = {
apps: [{
name: 'my-app',
script: 'app.js',
instances: 'max',
autorestart: true,
watch: false,
max_memory_restart: '1G',
env: {
NODE_ENV: 'development'
},
env_production: {
NODE_ENV: 'production'
}
}],
};

You can then start your application using the ecosystem file:

bash
pm2 start ecosystem.config.js --env production

• Remote Deployment: PM2 allows you to deploy your application remotely to different environments (development, staging, production) using deployment scripts. This streamlines the deployment process and ensures consistency across environments.

Conclusion:

PM2 is an invaluable tool for managing Node.js applications on Ubuntu servers. Its process management, load balancing, monitoring, and deployment features make it an essential part of any production environment. By following this comprehensive guide, you can effectively install and utilize PM2 to ensure the stability, performance, and uptime of your Node.js applications.

Further Exploration:

• PM2 Documentation: Refer to the official PM2 documentation for a detailed overview of all its features and options: https://pm2.keymetrics.io/docs/
• Keymetrics: Explore Keymetrics, PM2’s paid monitoring and management service, for advanced features like real-time monitoring, alerting, and remote control.

By mastering PM2, you’ll be well-equipped to manage your Node.js applications on Ubuntu server with confidence and efficiency. Good luck!