Kea unusual CPU utilization

Started by pfry, February 05, 2025, 08:21:55 PM

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February 05, 2025, 08:21:55 PM Last Edit: February 05, 2025, 10:28:31 PM by pfry Reason: Minimal data
I don't have a capture of the CPU figures - it wasn't terrible, but it was unusual. Restarting Kea calmed it down. Recommendations on what to capture if it happens again? The logs don't show anything unusual - just the "Lease File Cleanup" from the prior hour (~40 minutes prior). No related system logs.

Edit: Filling that out a bit, it looked to be eating 100% of one core for >15 minutes. Some sort of race, I imagine.

I'm also seeing unexpectedly high CPU that looks related to the kea-dhcp4 process. I don't know if it's the same as the issue shared above but in the interest of context, I'm replying here rather than starting a new thread.

Observed behavior:
  • The CPU widget on the dashboard shows all CPU cores hovering above 90%, often at 99%. I first noticed this back a couple weeks ago as of March 25, 2026 and it has persisted through a few updates but I don't have more specific historical version info.
  • Via shell (top), I can see that the kea-dhcp4 process is at 100% when no other process indicates it is taking up meaningful CPU capacity.
  • I do not see much of interest in the logs but I'm not sure I am looking comprehensively.
    • In the "General" log, I see no entries lower than Notice since last reboot and little that appears directly related. I do see the dhcp6c process issuing errors and exiting but I do not know if those could be related.
    • In /var/log/kea/latest.log I see two WARN messages that appear to be related to multi-threading being enabled then about 19 or so INFO logs per hour which seems expected.

My suspicion, given I have not seen many widespread reports of this, is that it is related to my configuration but I don't know if there are any diagnostics or other avenues I could pursue to determine the cause. I wanted to see if this is something anyone might have insight into before considering opening an OPNsense issue. If there is other information that might be useful to look further, please let me know. Thanks in advance for any help.