Create a custom threshold rule

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Create a custom threshold rule

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This functionality is in technical preview and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features.

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

  1. To access this page, go to ObservabilityAlerts.
  2. Click Manage RulesCreate rule.
  3. Under Select rule type, select Custom threshold.
Custom threshold alert configuration

Define rule data

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

  • Select a data view: Click the data view field to search for and select a data view that points to the indices or data streams that you’re creating a rule for. You can also create a new data view by clicking Create a data view. Refer to Create a data view for more on creating data views.
  • Define query filter (optional): Use a query filter to narrow down the data that the rule applies to. For example, set a query filter to a specific host name using the query filter host.name:host-1 to only apply the rule to that host.

Set rule conditions

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

Set aggregations
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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: The average value of a numeric field.
  • Max: The highest value of a numeric field.
  • Min: The lowest value of a numeric field.
  • Cardinality: The approximate number of unique values in a field.
  • Document count: The total number of documents in a field.
  • Sum: The total of a numeric field in your dataset.

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

  1. Set the Aggregation to Document count, and set the KQL Filter to log.level: "warn".
  2. Set the threshold to IS ABOVE 100 to trigger an alert when the number of log documents with a log level of warn reaches 100.
Set the equation and threshold
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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.

Basic math equation
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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:

  1. Set the following aggregations:

    • Aggregation A: Average system.cpu.user.pct
    • Aggregation B: Average system.cpu.system.pct
    • Aggregation C: Max system.cpu.cores.
  2. Set the equation to (A + B) / C * 100
  3. Set the threshold to IS ABOVE 95 to alert when CPU usage is above 95%.
Boolean logic
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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:

  1. Set the following aggregations:

    • Aggregation A: Sum kubernetes.statefulset.ready
    • Aggregation B: Sum kubernetes.statefulset.desired
  2. Set the equation to A == B ? 1 : 0. If A and B are equal, the result is 1. If they’re not equal, the result is 0.
  3. Set the threshold to IS BELOW 1 to trigger an alert when the result is 0 and the field values do not match.

Preview chart

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

Custom threshold preview chart

Group alerts by (optional)

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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.

When you select Alert me if a group stops reporting data, the rule is triggered if a group that previously reported metrics does not report them again over the expected time period.

Select role visibility

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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.

Action types

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

Alert action types

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.

Configure when a rule is triggered

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:

  • If alert matches query: Enter a KQL query that defines field-value pairs or query conditions that must be met for notifications to send. The query only searches alert documents in the indices specified for the rule.
  • If alert is generated during timeframe: Set timeframe details. Notifications are only sent if alerts are generated within the timeframe you define.
Configure a conditional alert
Action variables
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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.

Default notification message for logs threshold rules with open "Add variable" popup listing available action variables