Very high CPU usage in random moments, VPS goes down, can't find why
I have a small Hetzner VPS all with Docker containers running. My normal usage is fine. 1.7 GB Ram of 2.0 GB are in use (with buffers), uptime reports sane values all 3 around 0.60-0.90 (2 cores). Works pretty well.
In what I believe are random moments of the day, I receive a Hetrixtools notification that my stuff is down, and it is. Can't even login. In case it happens when I am logged in, I can't even give a command.
When it's over, uptime reports insane values, like 49.6 38.5 22.9 or something.
The issue: htop does not report anything out of the ordinary, docker stats the same.
All I see is typical processes which are using 2-10% of the CPU and small spikes of the usual suspects (a mysql process using 60% for a second or so).
Hetrixtools CPU monitor is even flatter. This is the last 24 hours according to it.
It does not make sense. I can't see what it is when it happens, and when I can see, nothing looks weird.
Anything else I could look at? It's even happening as I am writing this post now.
Edit: this looks ridicolous
To add to this, I am using Ubuntu 20.04, ufw enabled.