I run an old desktop mainboard as my homelab server. It runs Ubuntu smoothly at loads between 0.2 and 3 (whatever unit that is).
Problem:
Occasionally, the CPU load skyrockets above 400 (yes really), making the machine totally unresponsive. The only solution is the reset button.
Solution:
- I haven’t found what the cause might be, but I think that a reboot every few days would prevent it from ever happening. That could be done easily with a crontab line.
- alternatively, I would like to have some dead-simple script running in the background that simply looks at the CPU load and executes a reboot when the load climbs over a given threshold.
–> How could such a cpu-load-triggered reboot be implemented?
edit: I asked ChatGPT to help me create a script that is started by crontab every X minutes. The script has a kill-threshold that does a kill-9 on the top process, and a higher reboot-threshold that … reboots the machine. before doing either, or none of these, it will write a log line. I hope this will keep my system running, and I will review the log file to see how it fares. Or, it might inexplicable break my system. Fun!
Crontab to just auto reboot daily is probably better - if your PC becomes unresponsive I doubt it would be able to execute another script on top of everything. Ideally though, you’d do some log diving and figure out the cause.
This issue doesn’t happen very often, maybe every few weeks. That’s why I think a nightly reboot is overkill, and weekly might be missing the mark? But you are right in any case: regardless of what the cron says, the machine might never get around to executing it.