How does my CPU usage suddenly peak ?

Posted April 18, 2019 2.8k views
MonitoringUbuntu 18.04


Ubui am running an ubuntu 18.10 on a Droplet with enabled monitoring and have set it to notify me when CPU usage is higher than 80% for testing purposes.

What i noticed is that there was a sudden peak of 89% CPU Usage while the machine is powered on however not in use so i wonder if there is a way for me to know what processes have exploited CPU %?

Is this normal behaviour ?


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2 answers


It’s hard to say what it could be, it’s not particularly unusual. Perhaps someone tried a strong and distributed brute force attack against a public facing service. Perhaps you have a web server running and a crawler came along to hammer away at it.

If I ever need to get down to that kind of level and find out what happened at a specific time, I usually prefer syssnap to do the job. It’s made by cPanel but by no means requires their other software to be installed.


  • Thanks for your answer and suggestions Jarland,

    the situation is i have installed only GO lang with only 1 hello world printiln script and Yarn on that droplet.

    I was not using the machine and was not connected to it during the time when i received the alert. It says that local disk usage(read/write) was increased and droplet memory is up for 10%.

    I dont know if some automatic updates are enabled by default when instantiating a droplet, but i would like to clarify this behavior so i would not get surprised when i need to run monitoring for a more serious solution.

    Any guidance is appreciated,
    My best

I had the same problem now I found a solution I hope it will work for you.
actually, someone was attacking with a brute force attack on my website so why my website was down and the graph shows CPU 100% usage.

First of all, check which application takes much usage so enter the command “top” it will show the real-time CPU usage. in my case, PHP-fpm was taking 95% usage.

Now you have to check your Nginx log file.
sudo tail -f /var/log/nginx/access.log
it will show the error or bad gateway access details.. now you have to copy the IP address which is repeated a lot of times you have to block it.

You can block IP by using this command “iptables -I INPUT -s -j DROP

I hope this issue will be resolved.