Hello everyone,
UPDATE 
It took me another 2 hours to figure out, that the Issue #2 was caused by the Dockhand application. The second I started the container, the every 5 minutes spikes returned.
Now, I need to look into this container a bit closer, but I am not going to delete this thread, as it might be helpful for those affected by the same behavior.
Original Post
In short:
I have been running ZimaOS for at least 6 months now, currently on v.1.6.2 on Beelink ME Pro with N150 CPU and integrated Intel GPU. Just recently I started noticing regular, ever 1 and 5 minutes, CPU spikes for the very first time. Those spikes were also causing periodical increase of power consumption and rise of temperature.
Issue #1
Now, I have noticed regular CPU spikes using Beszel application at first:
To investigate it further, I used btop to help me find the problematic processes. It quickly turned out it was caused by the dockerd that was running the following command:
/usr/bin/dockerd --host=fd:// --add-runtime=nvidia=/usr/bin/nvidia-container-runtime
I do not own or use nVidia GPU, yet I have managed to find and rename the override.conf file under /etc/systemd/system/docker.service.d/ location that was responsible for triggering the CPU spikes.
It contains three lines:
[Service]
ExecStart=
ExecStart=/usr/bin/dockerd --host=fd:// --add-runtime=nvidia=/usr/bin/nvidia-container-runtime
By renaming it, for example, to override.conf.bak and running systemctl daemon-reload and systemctl restart docker I have managed to solve this issue.
Issue #2
However, yet another dockerd process was causing similar spikes, this time every exactly 5 minutes.
Thanks to btop I was able to gather some more information and take a couple of screenshots.
I have not managed to solve this one yet.
The process:
dockerd /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
From the last screenshot, it does seem like none of the running containers are at fault. It’s just one screenshot, but I have been observing both, btop and docker stats, running for over an hour, and I am quite certain the issue is not related to any of the installed applications.
—edited typos—