Create a custom threshold rule

Create a custom threshold rule to trigger an alert when an Observability data type reaches or exceeds a given value.

Specify the following settings to define the data the rule applies to:

Set the conditions for the rule to detect using aggregations, an equation, and a threshold.

Aggregations summarize your data to make it easier to analyze. Set any of the following aggregation types to gather data to create your rule: Average, Max, Min, Cardinality, Count, Sum, Percentile, or Rate. For more information about these options, refer to Aggregation options.

For example, to gather the total number of log documents with a log level of warn:

Set an equation using your aggregations. Based on the results of your equation, set a threshold to define when to trigger an alert. The equations use basic math or boolean logic. Refer to the following examples for possible use cases.

Add, subtract, multiply, or divide your aggregations to define conditions for alerting.

Example

Set an equation and threshold to trigger an alert when a metric is above a threshold. For this example, we’ll use average CPU usage—the percentage of CPU time spent in states other than idle or IOWait normalized by the number of CPU cores—and trigger an alert when CPU usage is above a specific percentage. To do this, set the following aggregations, equation, and threshold:

Use conditional operators and comparison operators with you aggregations to define conditions for alerting.

Example

Set an equation and threshold to trigger an alert when the number of stateful pods differs from the number of desired pods. For this example, we’ll use kubernetes.statefulset.ready and kubernetes.statefulset.desired, and trigger an alert when their values differ. To do this, set the following aggregations, equation, and threshold:

The preview chart provides a visualization of how many entries match your configuration. The shaded area shows the threshold you’ve set.

If you use the Group alerts by option, the maximum bar size will be 3. It will only show the top 3 fields.

Set one or more group alerts by fields for custom threshold rules to perform a composite aggregation against the selected fields. When any of these groups match the selected rule conditions, an alert is triggered per group.

When you select multiple groupings, the group name is separated by commas.

For example, if you group alerts by the host.name and host.architecture fields, and there are two hosts (Host A and Host B) and two architectures (Architecture A and Architecture B), the composite aggregation forms multiple groups.

If the Host A, Architecture A group matches the rule conditions, but the Host B, Architecture B group doesn’t, one alert is triggered for Host A, Architecture A.

If you select one field—for example, host.name—and Host A matches the conditions but Host B doesn’t, one alert is triggered for Host A. If both groups match the conditions, alerts are triggered for both groups.

Optionally configure the rule to trigger an alert when:

To do this, select Alert me if there’s no data.

The behavior of the alert depends on whether any group alerts by fields are specified:

You must select a scope value (Logs or Metrics), which affects the Kibana feature privileges that are required to access the rule. For example when it’s set to Logs, you must have the appropriate Observability > Logs feature privileges to view or edit the rule.

Extend your rules by connecting them to actions that use the following supported built-in integrations.

After you select a connector, you must set the action frequency. You can choose to create a summary of alerts on each check interval or on a custom interval. Alternatively, you can set the action frequency such that you choose how often the action runs (for example, at each check interval, only when the alert status changes, or at a custom action interval). In this case, you must also select the specific threshold condition that affects when actions run: Alert, No Data, or Recovered.

You can also further refine the conditions under which actions run by specifying that actions only run when they match a KQL query or when an alert occurs within a specific time frame:

Use the default notification message or customize it. You can add more context to the message by clicking the icon above the message text box and selecting from a list of available variables.

The following variables are specific to this rule type. You an also specify variables common to all rules.