Werk #22638: docker_container_status_uptime: Don't crash on container start time in the future

Component

Checks & agents

Title

docker_container_status_uptime: Don't crash on container start time in the future

Date

Oct 14, 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
2.5.0p16 Not yet released	Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT
2.4.0p38 Not yet released	Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

If the clock of a Docker node was ahead of the clock of the Checkmk server, a freshly started container reported a start time in the future. Its Uptime service then crashed with ValueError: Cannot render negative timespan.

The service now goes to UNKNOWN and states how far the container start time lies in the future, pointing to the clock synchronization between the Docker node and the Checkmk server.

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