Documentationbreadcrumb arrow Pluginsbreadcrumb arrow Prometheus Alertingbreadcrumb arrow Configure alert rulesbreadcrumb arrow Create an alert rule
Open source Enterprise Grafana Cloud
Last reviewed: August 19, 2026

Create an alert rule

An alerting rule watches an expression and produces alerts when it returns results.

Before you begin

  • Make sure you have the alert.rules.external:write permission.
  • Make sure the data source you’re writing to supports a ruler API.

Create the rule

  1. Click Rules in the plugin navigation.
  2. Click New alert rule.
  3. Under Define alert rule, enter a Name. This becomes the alert’s alertname label, so make it descriptive and stable. Renaming it later creates what Alertmanager treats as a different alert.
  4. Select the Data source to write the rule to. The query editor can’t load until you’ve chosen one.
  5. Write the Expression. Write it so that it returns nothing when everything is healthy, and returns one series per problem otherwise. Refer to Queries and conditions.
  6. Set the Pending period, which is how long the condition has to hold before the alert fires. Select None to fire on the first matching evaluation.
  7. Optionally set Keep firing for, which is how long the alert keeps firing after the condition stops being met. Leave it empty to resolve as soon as the condition clears. It takes a duration like 5m, or a compound one like 1h30m.
  8. Choose a Namespace and Group. Both pickers search existing values as you type and let you create a new one if nothing matches.
  9. Add Labels for routing. Click Add labels to open the label editor.
  10. Add Annotations describing what happened and what to do about it. Click Add custom annotation for keys beyond the standard ones.
  11. Click Save.

Names, namespaces, and groups are each limited to 255 characters, and all are required.

Check the expression before saving

The editor includes a Query Preview. Click Run query to execute the expression against the data source and see what comes back, paged if there are many series.

This is the single most useful step in the form. The preview tells you how many alert instances the rule will produce right now. No rows means the rule fires nothing, and a hundred rows means a hundred alerts. It’s much easier to notice a missing aggregation here than after the rule is live.

After saving

Rules take a few seconds to reach the ruler. The plugin shows that the rule is being propagated and refreshes on its own when it lands, so an empty-looking rule immediately after saving is expected.

Once it appears, check its health on the rule detail page. A rule showing error health isn’t watching anything. Refer to Alert rule state and health.

Other actions on a rule

From the rule list and detail pages:

ActionWhat it does
EditChange the rule in place
DuplicateCreate a copy to edit as a new rule
ExportDownload the rule definition, or copy it to the clipboard
Copy linkCopy a direct URL to the rule
Silence notificationsCreate a silence pre-filled with this rule’s matchers
DeleteRemove the rule from its group

Duplicate and Edit are only available for rules on data sources with a ruler API. The plugin says so rather than failing when you try.

Export works everywhere, including read-only Prometheus sources, which makes it a practical way to copy a rule out of Prometheus and into Mimir.

Delete a rule

  1. Open the rule.
  2. Click Delete.
  3. Confirm. The dialog box names the rule, its group, and its namespace, since names alone are easy to confuse.

Deletion can’t be undone. As with creation, the plugin waits for the change to propagate before showing the updated list.