Invoke-IcingaCheckPerfCounter Plugin Behavior with Missing Performance Counters

[ispmonsupporto]

Introduction: During a mass deployment for metric collection using the Invoke-IcingaCheckPerfCounter plugin in a client’s infrastructure, an issue was identified related to the handling of missing performance counters.
Specifically, the -IgnoreEmptyChecks option, which is meant to prevent the plugin from returning an UNKNOWN exit code when a performance counter is not present, is not working as expected.

Problem Description:
When the Invoke-IcingaCheckPerfCounter plugin is used with the -IgnoreEmptyChecks option, the expected behavior is that if the specified performance counter does not exist on the server, the plugin should ignore the check without returning an UNKNOWN error. However, when the counter is missing, the plugin still returns UNKNOWN despite the option being correctly configured.

When the performance counter exists: Running the command with an existing performance counter:
Invoke-IcingaCheckPerfCounter -IgnoreEmptyChecks -PerfCounter '\Hyper-V Hypervisor Logical Processor(_Total)% Total Run Time' -Verbosity 3

Expected result: The plugin returns the performance counter value, and the exit code is a valid result (e.g., OK or WARNING, depending on the collected data).

When the performance counter does not exist: Running the command with a missing performance counter:
Invoke-IcingaCheckPerfCounter -IgnoreEmptyChecks -PerfCounter '\Hyper-V Hypervisor Virtual Processor(_Total)\CPU Wait Time Per Dispatch' -Verbosity 3

Observed result: Despite having the -IgnoreEmptyChecks option enabled, the plugin still returns an UNKNOWN error instead of ignoring the check as expected.

Versions of components in use on the server

Icinga PowerShell Framework v1.12.3
PowerShell Version => 4.0
Operating System => Microsoft Windows Server 2012 R2 Datacenter
Operating System Version => 6.3.9600

Installed components on this system:

Is it possible to get an OK status when the counter is not found? Can this be fixed?

Regard
Mirko M.

[LordHepipud]

Thank you for the issue. The reason why the ignore flags do not work in this case, is because the Performance Counter exception in this case is a low-level exception directly issued by the Icinga for Windows core.

The -IgnoreEmptyChecks flag is only covering if the plugin does not return an object to check, while the "Performance Counter not found" error is an exception thrown, to inform the user something went wrong.

The best solution for this would be to add a flag "IgnoreMissingCounters" instead.

[K0nne]

We also have this issue on empty hyperv hosts. The counter only exists when vm's are present.