4ad517f996
Kibana Alerting is now the preferred method for alerting in Elastic. To avoid confusion, we should use "Watcher" and avoid terms like "Elasticsearch alerting." This updates a reference on the Alerting page. Relates to https://github.com/elastic/elasticsearch/pull/75220
142 lines
8.7 KiB
Text
142 lines
8.7 KiB
Text
[role="xpack"]
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[[alerting-getting-started]]
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= Alerting
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--
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Alerting allows you to define *rules* to detect complex conditions within different {kib} apps and trigger actions when those conditions are met. Alerting is integrated with {observability-guide}/create-alerts.html[*Observability*], {security-guide}/prebuilt-rules.html[*Security*], <<geo-alerting,*Maps*>> and {ml-docs}/ml-configuring-alerts.html[*{ml-app}*], can be centrally managed from the <<management,*Management*>> UI, and provides a set of built-in <<action-types, connectors>> and <<stack-rules, rules>> (known as stack rules) for you to use.
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image::images/alerting-overview.png[Rules and Connectors UI]
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[IMPORTANT]
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==============================================
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To make sure you can access alerting and actions, see the <<alerting-prerequisites, setup and pre-requisites>> section.
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==============================================
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[float]
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== Concepts and terminology
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Alerting works by running checks on a schedule to detect conditions defined by a *rule*. When a condition is met, the rule tracks it as an *alert* and responds by triggering one or more *actions*.
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Actions typically involve interaction with {kib} services or third party integrations. *Connectors* allow actions to talk to these services and integrations.
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This section describes all of these elements and how they operate together.
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[float]
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=== Rules
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A rule specifies a background task that runs on the {kib} server to check for specific conditions. {kib} provides two types of rules: stack rules that are built into {kib} and domain rules that are registered by Kibana apps. Refer to <<rule-types,Rule types>> for more information.
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A rule consists of three main parts:
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* *Conditions*: what needs to be detected?
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* *Schedule*: when/how often should detection checks run?
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* *Actions*: what happens when a condition is detected?
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For example, when monitoring a set of servers, a rule might:
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* Check for average CPU usage > 0.9 on each server for the last two minutes (condition).
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* Check every minute (schedule).
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* Send a warning email message via SMTP with subject `CPU on {{server}} is high` (action).
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image::images/what-is-a-rule.svg[Three components of a rule]
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The following sections describe each part of the rule in more detail.
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[float]
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[[alerting-concepts-conditions]]
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==== Conditions
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Under the hood, {kib} rules detect conditions by running a Javascript function on the {kib} server, which gives it the flexibility to support a wide range of conditions, anything from the results of a simple {es} query to heavy computations involving data from multiple sources or external systems.
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These conditions are packaged and exposed as *rule types*. A rule type hides the underlying details of the condition, and exposes a set of parameters
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to control the details of the conditions to detect.
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For example, an <<rule-type-index-threshold, index threshold rule type>> lets you specify the index to query, an aggregation field, and a time window, but the details of the underlying {es} query are hidden.
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See <<stack-rules>> and <<domain-specific-rules>> for the types of rules provided by {kib} and how they express their conditions.
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[float]
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[[alerting-concepts-scheduling]]
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==== Schedule
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Rule schedules are defined as an interval between subsequent checks, and can range from a few seconds to months.
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[IMPORTANT]
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==============================================
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The intervals of rule checks in {kib} are approximate. The timing of their execution is affected by factors such as the frequency at which tasks are claimed and the task load on the system. See <<alerting-production-considerations, Alerting production considerations>> for more information.
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==============================================
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[float]
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[[alerting-concepts-actions]]
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==== Actions
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Actions are invocations of connectors, which allow interaction with {kib} services or integrations with third-party systems. Actions run as background tasks on the {kib} server when rule conditions are met.
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When defining actions in a rule, you specify:
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* The *connector type*: the type of service or integration to use
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* The connection for that type by referencing a <<alerting-concepts-connectors, connector>>
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* A mapping of rule values to properties exposed for that type of action
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The result is a template: all the parameters needed to invoke a service are supplied except for specific values that are only known at the time the rule condition is detected.
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In the server monitoring example, the `email` connector type is used, and `server` is mapped to the body of the email, using the template string `CPU on {{server}} is high`.
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When the rule detects the condition, it creates an <<alerting-concepts-alerts, alert>> containing the details of the condition, renders the template with these details such as server name, and executes the action on the {kib} server by invoking the `email` connector type.
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image::images/what-is-an-action.svg[Actions are like templates that are rendered when an alert detects a condition]
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See <<action-types>> for details on the types of connectors provided by {kib}.
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[float]
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[[alerting-concepts-alerts]]
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=== Alerts
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When checking for a condition, a rule might identify multiple occurrences of the condition. {kib} tracks each of these *alerts* separately and takes an action per alert.
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Using the server monitoring example, each server with average CPU > 0.9 is tracked as an alert. This means a separate email is sent for each server that exceeds the threshold.
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image::images/alerts.svg[{kib} tracks each detected condition as an alert and takes action on each alert]
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[float]
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[[alerting-concepts-connectors]]
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=== Connectors
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Actions often involve connecting with services inside {kib} or integrating with third-party systems.
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Rather than repeatedly entering connection information and credentials for each action, {kib} simplifies action setup using *connectors*.
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*Connectors* provide a central place to store connection information for services and integrations. For example if four rules send email notifications via the same SMTP service, they can all reference the same SMTP connector. When the SMTP settings change, you can update them once in the connector, instead of having to update four rules.
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image::images/rule-concepts-connectors.svg[Connectors provide a central place to store service connection settings]
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[float]
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== Putting it all together
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A *rule* consists of conditions, *actions*, and a schedule. When conditions are met, *alerts* are created that render *actions* and invoke them. To make action setup and update easier, actions use *connectors* that centralize the information used to connect with {kib} services and third-party integrations. The following example ties these concepts together:
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image::images/rule-concepts-summary.svg[Rules, connectors, alerts and actions work together to convert detection into action]
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. Anytime a *rule*'s conditions are met, an *alert* is created. This example checks for servers with average CPU > 0.9. Three servers meet the condition, so three alerts are created.
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. Alerts create *actions* as long as they are not muted or throttled. When actions are created, the template that was setup in the rule is filled with actual values. In this example, three actions are created, and the template string {{server}} is replaced with the server name for each alert.
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. {kib} invokes the actions, sending them to a third party *integration* like an email service.
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. If the third party integration has connection parameters or credentials, {kib} will fetch these from the *connector* referenced in the action.
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[float]
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[[alerting-concepts-differences]]
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== Differences from Watcher
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{kib} alerting and <<watcher-ui,Watcher>> are both used to detect conditions and can trigger actions in response, but they are completely independent alerting systems.
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This section will clarify some of the important differences in the function and intent of the two systems.
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Functionally, {kib} alerting differs in that:
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* Scheduled checks are run on {kib} instead of {es}
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* {kib} <<alerting-concepts-conditions, rules hide the details of detecting conditions>> through *rule types*, whereas watches provide low-level control over inputs, conditions, and transformations.
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* {kib} rules track and persist the state of each detected condition through *alerts*. This makes it possible to mute and throttle individual alerts, and detect changes in state such as resolution.
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* Actions are linked to *alerts* in {kib} alerting. Actions are fired for each occurrence of a detected condition, rather than for the entire rule.
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At a higher level, {kib} alerting allows rich integrations across use cases like <<xpack-apm,*APM*>>, <<metrics-app,*Metrics*>>, <<xpack-siem,*Security*>>, and <<uptime-app,*Uptime*>>.
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Pre-packaged *rule types* simplify setup and hide the details of complex, domain-specific detections, while providing a consistent interface across {kib}.
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--
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