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Add a derived data policy

You can generate new metrics as calculations from existing metrics and numeric entity attributes with a derived data policy.

This task assumes that you have opened the ADD POLICY dialog box in the Policies tab in ADMIN > Policy.

  1. If you haven't already done so, set the Enabled option to activate the policy or deactivate it, and enter a name for your policy. Policy names can't be changed after the ADD POLICY dialog box is saved.

  2. After you select the derived data type, the dialog box updates to ADD A DERIVED DATA POLICY.

  3. Enter the remaining information in the General info tab.

  4. Click Main details and enter the derived data information for your policy.

  5. Input the cycle time (in milliseconds) at which your policy should be applied

  6. Enter the criteria for the scope of entities and metrics from which and on which new datapoints will be computed.

  7. For each datapoint you intend to add, click ADD DATAPOINT.

  8. Enter the datapoint name.

  9. Enter the datapoint source code in CEL format. A datapoint expression may reference any metric belonging to an entity as well as any numeric attribute for the anchor entity or its parent entity.

    1. Example datapoint calculation definitions:

      • metric.mem_usage / metric.mem_total - computes the ratio of memory usage to total memory for an entity
      • metric["ping.http.down_subpages_count"] + metric["ping.http.up_subpages_count"] - computes the total number of subpages for a ping.http metric

    2. Valid datapoint references:

      • metric.{METRIC_NAME} e.g. metric.mem_usage
      • metric["{METRIC_NAME}"] e.g. metric["ping.http.down_subpages_count"] In CEL format, the . symbol is interpreted as an accessor operator, so metric names with . in them must be referenced with the [""] syntax.

    3. Valid attribute references:

      • entity.{ATTRIBUTE_NAME} e.g. entity.mem_total
      • parent.{ATTRIBUTE_NAME} e.g. parent.mem_total
      • entity["{ATTRIBUTE_NAME}"] e.g. entity["mem_total"] In CEL format, the . symbol is interpreted as an accessor operator, so attribute names with . in them must be referenced with the [""] syntax.

  10. Click SAVE.