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How can we alert on whether a metric value is zero or has stopped reporting?

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Article ID: 189243

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Updated On:

Products

CA Application Performance Management Agent (APM / Wily / Introscope) CA Application Performance Management (APM / Wily / Introscope) INTROSCOPE DX Application Performance Management

Issue/Introduction

We need to know when a metric value is zero or has stopped reporting but as far as we can see alerts do not allow you to report against a metric that has no value - is there a way to achieve this?

Environment

Release : 10.x

Component : APM 

Resolution

Because alerts need a value to compare against it is first necessary to generate a metric value for situations where the metric is not reporting. This can be done using a calculator.

First create a metric grouping from the metric on which you need to alert. 





Note in this example the Agent Expression includes a wildcard - if you have multiple hosts that match then this would need to be restricted as the metric grouping must match ONLY the single metric being monitored

As you can see in this example the metric stops reporting directly.

Then create a calculator against that metric grouping (#1) - select the operation (#2) to be Sum and this will then add up the values in the metric grouping (which effectively means the metric itself) - the advantage of this is that adding nothing i.e. no data value is still zero so the calculator output will always have a value. You choose the name for the output metric (#3)



The output will appear as a metric in the investigator and that is something that alerts can be configured against.



If there are multiple metrics that need to be evaluated and alerted against this is still possible in one alert.

Define the metric grouping that the alert evaluates against to match the calculator output metrics for the Calculators that were created for the individual metrics.





Now create and alert against that metric grouping. The alert criteria should be set to Combination Any and notify by individual metric



The alert will then trigger against any of the calculator values that shows 0





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