Werk #22238: Micro Core no longer stops when an alert handler is slow to accept an event
| Component | The Checkmk Micro Core | ||||||
| Title | Micro Core no longer stops when an alert handler is slow to accept an event | ||||||
| Date | Sep 3, 2026 | ||||||
| Level | Prominent Change | ||||||
| Class | Bug Fix | ||||||
| Compatibility | Compatible - no manual interaction needed | ||||||
| Checkmk versions & editions |
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On sites that use alert handlers, the Checkmk Micro Core could stop
unexpectedly. Monitoring then paused until the core came back up, and
cmc.log ended with
cannot send alert data: Connection timed out
The core stopped when it could not pass an event to an alert handler quickly enough, typically while the alert handler was restarting itself after a configuration change. Such a delay passes on its own, but the core treated it as fatal.
The core now keeps monitoring and delivers the event as soon as the alert handler accepts it.