I'm running Ubuntu Server 20.04 fully up-to-date with a Raspberry Pi 4, 4GB of RAM (may be relevant or not, but system is running with an SSD through an USB3.0 port) as a low-power PC capable of running some Docker images. It runs xfce4 displaying a Magic Mirror, and it recollects some data through the GPIO ports (which takes only a few mA): power supply is an original 3A power adapter.
The problem I'm having is that today it lost the ethernet connection but the rpi itself kept on running just fine... until I plugged in a keyboard at which point it just kernel panicked or so. No logging at that point available to know what happened there.
When I checked out the journal, the following caught my attention: https://pastebin.com/0VNDSUyL
At the time, memory usage was about 90% according to the latest data available (I run Telegraf and log everything to an Influxdb instance running [both with Docker] on the same machine).
The process that was killed was Java, but I don't know which Docker image it was because the runtime isn't even installed on the host.
- Is this an indicator that I am running low on RAM? What can I do to avoid this problem in the future?
- Why did the OOM-killer kicked in while I still had about 10% of RAM left? Is this tweakable?
- Why did it kill my ethernet connection? Did it left the system in an unstable condition?
- Can it be something hardware related that is creating this issue?
I don't know where to look further atm, so any help here would be very much appreciated! If you need more details, just ask :)
I have no swap enabled on this system:
ubuntu@unifi:~ $ free -h total used free shared buff/cache available Mem: 3.7Gi 2.7Gi 190Mi 203Mi 826Mi 886Mi Swap: 0B 0B 0B ubuntu@unifi:~ $ grep -i swap /etc/fstab ubuntu@unifi:~ $