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Werk #22112: Nagios: no more check results for disabled services

Component Core & setup
Title Nagios: no more check results for disabled services
Date Sep 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
2.5.0p14
Not yet released
Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

With the Nagios core, a service disabled via the ruleset Disabled services could still be checked, and its result written to the check result queue. As the core has no definition for such a service, Nagios logged a warning for every result it was unable to assign, flooding var/log/nagios.log:

Warning: Check result queue contained results for service 'Unimplemented check
foo' on host 'HOSTNAME', but the service could not be found!  Perhaps you
forgot to define the service in your config files?

Affected were hosts on which all services of a check plug-in are disabled. A precompiled host check only loads the plug-ins of the services it is supposed to check. If a plug-in was left out that way, the host check could no longer compute the names of that plug-in's services, and the ruleset Disabled services, which matches on the service name, no longer applied to them.

Hosts on which at least one service of the plug-in remained enabled were never affected, and neither was the Checkmk Micro Core.

Please note that a service which has been discovered since the last activation of changes is still checked even if a Disabled services rule matches it, until changes are activated again.

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