2. Tutorials
  3. PM2 — CPU/Memory Monitoring

PM2 — CPU/Memory Monitoring

The previous posts within this series guided you through the topics of process management, how to display currently managed app instance processes and how to restart your applications after system reboots. With PM2, you can also monitor your app processes in respect of CPU and memory utilization. This article will show you how to use this built-in monitoring feature.

PM2 Series Overview

  1. Utility Overview & Installation
  2. Series Round-Up
  3. Using Bun to Start Your App
  4. Use TSX to Start Your App
  1. Process Management
  2. List Processes and Show Process Details
  3. Restart Processes After System Reboot
  4. Cluster Mode and Zero-Downtime Restarts
  5. Apply Actions to a Selected Process in Process File (JSON/JS/YAML)
  1. Advanced App Configuration with JSON File
  2. Module System
  3. Create Multiple Environments in Process File (JSON/JS/YAML)
  1. How to Start Your App With Node.js V8 Arguments
  2. Use NPM to Start Your App
  3. Start Node.js App With Increased Memory Limit From Command Line
  4. Start Node.js App With Increased Memory Limit From JSON Configuration
  5. Start Multiple Apps With A Single Process File (JSON/JS/YAML)

Monitoring With PM2

Actually, the PM2 command line utility makes it very easy to show the current CPU and memory utilization for each of your managed application processes. The only command you need to remember is:

pm2 monit

You’ll see a real-time overview of your managed apps and respectively the process name, CPU and memory utilization in MB. To illustrate the monitoring command, we’ve started our Future Studio homepage and maintenance servers side by side locally. Since currently nobody accesses any of both apps, they’re idling and waiting for work. The default memory consumption is about 50M for the maintenance and 70M for the homepage project.

$ pm2 monit
⌬ PM2 monitoring (To go further check out https://app.keymetrics.io)

 ● maintenance               [                         ] 0 %
[0] [fork_mode]              [||||||||                 ] 48.281 MB

 ● homepage                  [                         ] 0 %
[2] [fork_mode]              [||||||||||||             ] 68.777 MB

That’s all the magic. Keymetrics (the developers of PM2) uses this feature to report the current process utilization directly to their dashboard which is accessible via web interface. If you don’t have any other system utilization mechanism in place, PM2’s monitoring feature will at least give you a sense of your apps utilization levels.

What Comes Next

This article describes how to use PM2’s built-in monitoring utility to show the app’s real-time utilization for CPU and memory.

The upcoming article will guide you through the required steps to run your app instances in cluster mode. Additionally, we’ll show you how to use the cluster mode to deploy app updates with 0s downtimes. You don’t need to worry about unavailability anymore!

If you’ve questions about PM2 and the integrated monitoring, leave a comment below or reach out @futurestud_io.

Marcus Pöhls

Marcus is a fullstack JS developer. He’s passionate about the hapi framework for Node.js and loves to build web apps and APIs. Creator of Futureflix and the “learn hapi” learning path.

Explore the Library

Find interesting tutorials and solutions for your problems.

Android

Node.js

Server

Miscellaneous