Werk #22515: Averaging checks: Fix ZeroDivisionError after time anomalies

Component

Checks & agents

Title

Averaging checks: Fix ZeroDivisionError after time anomalies

Date

Sep 29, 2026

Level

Trivial Change

Class

Bug Fix

Compatibility

Compatible - no manual interaction needed

Checkmk versions & editions

3.0.0b1 Not yet released	Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT
2.5.0p15	Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

Checks that average their values over time could crash with ZeroDivisionError: float division by zero. This was seen with the Proxmox VE CPU Utilization service when averaging is configured: it uses the uptime of the VM as its clock, and if the reported uptime stepped back and then returned to exactly the time at which averaging had started, the next check crashed.

This case is now treated like other time anomalies, and the service keeps reporting the averaged value.

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