In my previous post, I shared about my debugging process using various Linux tools and debugger. During the process, I came across the analysis technique using flame graphs and thought it will be interesting to see what information I can get out of it.

What are flame graphs?

Flame graphs, as the name suggests, are graphs that look like flames because of the shape and color (usually red-yellowish hues). It was invented by Brendan Gregg for the purpose of analyzing performance issue and understand CPU usage quickly.

Recently one of our nodejs application (responsible for scraping metrics for external services) running in our EKS cluster was experiencing high CPU usage and memory leak and I was tasked to figure out the root cause. In this post, I will share my troubleshooting process and interesting stuff I discovered along the way.

It all began with an alert notifying us of the application experiencing CPU throttling. Looking at the dashboard, it became apparent that high CPU usage isn’t the only issue; it was also experiencing memory leak and oddly high incoming and outgoing traffic.