DocumentationGrafana documentationAlertingIntroduction

Introduction to Alerting

Whether you’re just starting out or you’re a more experienced user of Grafana Alerting, learn more about the fundamentals and available features that help you create, manage, and respond to alerts; and improve your team’s ability to resolve issues quickly. For a hands-on introduction, refer to our tutorial to get started with Grafana Alerting.

The following diagram gives you an overview of Grafana Alerting and introduces you to some of the fundamental features that are the principles of how Grafana Alerting works.

How it works at a glance

• Grafana Alerting periodically queries data sources and evaluates the condition defined in the alert rule
• If the condition is breached, an alert instance fires
• Firing (and resolved) alert instances are sent for notifications, either directly to a contact point or through notification policies for more flexibility

Fundamentals

The following concepts are key to your understanding of how Grafana Alerting works.

Alert rules

An alert rule consists of one or more queries and expressions that select the data you want to measure. It also contains a condition, which is the threshold that an alert rule must meet or exceed to fire.

In the alert rule, choose the contact point or notification policies to determine how to receive the alert notifications.

Alert instances

Each alert rule can produce multiple alert instances (also known as alerts) - one alert instance for each time series. This is exceptionally powerful as it allows you to observe multiple series in a single expression.

promql Copy

sum by(cpu) (
  rate(node_cpu_seconds_total{mode!="idle"}[1m])
)

A rule using the PromQL expression above creates as many alert instances as the amount of CPUs after the first evaluation, enabling a single rule to report the status of each CPU.

Alert rules are frequently evaluated and the state of their alert instances is updated accordingly. Only alert instances that are in a firing or resolved state are sent in notifications.

Contact points

Contact points determine the notification message and where notifications are sent. For example, you might have a contact point that sends notifications to an email address, to Slack, to an incident management system (IRM) such as Grafana OnCall or Pagerduty, or to a webhook.

In the alert rule, you can choose a contact point to receive the alert notifications or use notification policies instead.

Notification policies

Notification policies provide a flexible method to handle alert notifications for larger systems.

Notification policies routes alerts to contact points via label matching. Each notification policy consists of a set of label matchers (0 or more) that specify which alert instances (identified by their labels) they handle. Notification policies are defined in a tree structure, where the root of the notification policy tree is the Default notification policy, which ensures all alert instances are handled.

Each notification policy decides where to send the alert (contact point) and when to send the notification (timing options). Additionally, it can group multiple firing alert instances into a single notification to reduce alert noise.

Silences and mute timings

Silences and mute timings allow you to pause notifications for specific alerts or even entire notification policies. Use a silence to pause notifications on an ad-hoc basis, such as during a maintenance window; and use mute timings to pause notifications at regular intervals, such as evenings and weekends.

Architecture

Grafana Alerting is built on the Prometheus model of designing alerting systems. Prometheus-based alerting systems have two main components:

• An alert generator that evaluates alert rules and sends firing and resolved alerts to the alert receiver.
• An alert receiver (also known as Alertmanager) that receives the alerts and is responsible for handling them and sending their notifications.

Grafana Alerting doesn’t use Prometheus as its default alert generator because it works with many other data sources; not just Prometheus.

However, Grafana can also use Prometheus as an alert generator (refer to alert rule types), as well as external Alertmanagers.

Design your Alerting system

Monitoring complex IT systems and understanding whether everything is up and running correctly is a difficult task. Setting up an effective alert management system is therefore essential to inform you when things are going wrong before they start to impact your business outcomes.

Designing and configuring an alert management set up that works takes time.

Here are some tips on how to create an effective alert management set up for your business:

Which are the key metrics for your business that you want to monitor and alert on?

• Find events that are important to know about and not so trivial or frequent that recipients ignore them.

• Alerts should only be created for big events that require immediate attention or intervention.

• Consider quality over quantity.

Which type of Alerting do you want to use?

• Choose between Grafana-managed Alerting or Grafana Mimir or Loki-managed Alerting; or both.

How do you want to organize your alerts and notifications?

• Be selective about who you set to receive alerts. Consider sending them to whoever is on call or a specific Slack channel.
• Automate as far as possible using the Alerting API or alerts as code (Terraform).

How can you reduce alert fatigue?

• Avoid noisy, unnecessary alerts by using silences, mute timings, or pausing alert rule evaluation.
• Continually tune your alert rules to review effectiveness. Remove alert rules to avoid duplication or ineffective alerts.
• Think carefully about priority and severity levels.
• Continually review your thresholds and evaluation rules.