Quickly generating CPU load on a Linux machine 🔥

I needed to test an OCI Alarm I had created that should send an e-mail notification when the average CPU utilisation of a server exceeds 50% over a 15-minute period.

I found a “quick and dirty” way to generate CPU load on Linux using this one simple command:

yes > /dev/null &

This command runs yes (which outputs an endless stream of “y” lines) and redirects all its output to /dev/null (discarding it), with & putting it in the background.

If I then ran htop on the instance, I could see that this pegged the CPU at 100%!

After 15 minutes, I received a lovely alert in my inbox:

If you do this, don’t forget to kill the process afterwards using “killall yes”.