Configure an alert to track a custom metric

You can configure a threshold or trend alert to track a custom metric. For top-level (or base) metrics, you can create an alert for any metric type—count, dataset, or sampleset. However, for detail metrics, you can only create an alert for the count metric type.

1. Log into the Web UI on the ExtraHop Discover or Command appliance.
2. Click the System Settings icon and then click Metric Catalog.
3. Find the custom metric you want to track and note the following fields from the Parameters section:
   • Metric
   • Source Type
   • Metric Type
   • Type

   
4. Close the Metric Catalog, click the System Settings icon , and then click Alerts.
5. Click New to open the Alert Configuration window.
6. In the Name field, type a unique name for the alert.
7. From the Alert Type options, select the type of alert that you want to configure.

   Option	Description
   Threshold	Threshold-based alerts are generated when a monitored metric crosses a defined value in a time period. You can specify a top-level or a detail metric as the threshold.
   Trend	Trend-based alerts are generated when a monitored metric deviates from the normal trends observed by the system.

   Note:

   You cannot configure a detection alert to track a specific metric.

8. For Threshold alerts, from the Detail options, select the type of metric that corresponds to the Type field that you noted previously from the Metric Catalog. (Skip this step for Trend alerts.)
9. Click the Select metric icon and complete the following steps to find the custom metric you want to track.
   These entries must correspond to the parameters you noted previously from fields in the Metric Catalog.
   1. Click the arrow next to the entry that corresponds to the Source Type field, such as device.
   2. From the expanded list, click the arrow next to custom.
   3. From the expanded list, select the entry that corresponds to the Metric Type field.
      For example, if the entry in the Metric Catalog is Count, click custom_count in the list.
   4. In the Key pattern field, type the name of the custom metric that corresponds to the Metric field, such as HTTP_RESPONSE_device_detail_count_uri.
      The completed selection will look similar to the following figure.
      
      
   5. Click OK.
10. From the Firing Mode options, select the mode that indicates when to generate an alert.

    Option	Description
    Edge-triggered	An edge-triggered alert is generated only once when the alert conditions are true. The alert is generated again only if conditions are true after the metric value has returned to normal conditions twice.
    Level-triggered	A level-triggered alert is generated continuously while the alert conditions are true for the specified time period.

11. From the Alert When options, configure the alert expression that specifies when to issue an alert.
    Alert expression options differ by alert type. For more information, see the following topics:

    • Configure threshold alert settings
    • Configure trend alert settings
12. Click OK.