Grafana allows you to create alerting rules that query one or more data sources, reduce or transform the results and compare them to each other or to fixed thresholds. When these are executed, Grafana sends notifications to the contact point. For information on Grafana Alerting, see [About Grafana Alerting]({{< relref "../" >}}) which explains the various components of Grafana Alerting. We also recommend that you familiarize yourself with some of the [fundamental concepts]({{< relref "../fundamentals/" >}}) of Grafana Alerting.
- In **Rule name**, add a descriptive name. This name is displayed in the alert rule list. It is also the `alertname` label for every alert instance that is created from this rule.
1. In Step 2, add queries and expressions to evaluate, and then select the alert condition.
- Add one or more [queries]({{< relref "/docs/grafana/latest/panels-visualizations/query-transform-data#add-a-query" >}}) or [expressions]({{< relref "/docs/grafana/latest/panels-visualizations/query-transform-data/expression-queries" >}}).
- For each expression, select either **Classic condition** to create a single alert rule, or choose from the **Math**, **Reduce**, and **Resample** options to generate separate alert for each series. For details on these options, see [Single and multi dimensional rule](#single-and-multi-dimensional-rule).
> **Note:** Once a condition is breached, the alert goes into the Pending state. If the condition remains breached for the duration specified, the alert transitions to the `Firing` state, otherwise it reverts back to the `Normal` state.
- In **Configure no data and error handling**, configure alerting behavior in the absence of data. Use the guidelines in [No data and error handling](#no-data-and-error-handling).
You can pause alert rule evaluation to prevent noisy alerting while tuning your alerts. Pausing stops alert rule evaluation and does not create any alert instances. This is different to mute timings, which stop notifications from being delivered, but still allow for alert rule evaluation and the creation of alert instances.
- For **Group**, specify a pre-defined group. Newly created rules are appended to the end of the group. Rules within a group are run sequentially at a regular interval, with the same evaluation time.
- Add a description and summary to customize alert messages. Use the guidelines in [Annotations and labels for alerting]({{< relref "../fundamentals/annotation-label/" >}}).
For Grafana managed alerts, you can create a rule with a classic condition or you can create a multi-dimensional rule.
**Rule with classic condition**
Use the classic condition expression to create a rule that triggers a single alert when its condition is met. For a query that returns multiple series, Grafana does not track the alert state of each series. As a result, Grafana sends only a single alert even when alert conditions are met for multiple series.
**Multi dimensional rule**
To generate a separate alert for each series, create a multi-dimensional rule. Use `Math`, `Reduce`, or `Resample` expressions to create a multi-dimensional rule. For example:
- Add a `Reduce` expression for each query to aggregate values in the selected time range into a single value. (Not needed for [rules using numeric data]({{< relref "../fundamentals/evaluate-grafana-alerts/#alerting-on-numeric-data-1" >}})).
- Add a `Math` expression with the condition for the rule. Not needed in case a query or a reduce expression already returns 0 if rule should not fire, or a positive number if it should fire. Some examples: `$B > 70` if it should fire in case value of B query/expression is more than 70. `$B < $C * 100` in case it should fire if value of B is less than value of C multiplied by 100. If queries being compared have multiple series in their results, series from different queries are matched if they have the same labels or one is a subset of the other.
> **Note:** Grafana does not support alert queries with template variables. More information is available at <https://community.grafana.com/t/template-variables-are-not-supported-in-alert-queries-while-setting-up-alert/2514>.
For more information, see [expressions documentation]({{< relref "/docs/grafana/latest/panels-visualizations/query-transform-data/expression-queries" >}}).
**Note:** Alert rules that are configured to fire when an evaluation returns no data or error only fire when the entire duration of the evaluation period has finished. This means that rather than immediately firing when the alert rule condition is breached, the alert rule waits until the time set as the **For** field has finished and then fires, reducing alert noise and allowing for temporary data availability issues.
| No Data | Creates a new alert `DatasourceNoData` with the name and UID of the alert rule, and UID of the datasource that returned no data as labels. |
| Alerting | Sets alert rule state to `Alerting`. The alert rule waits until the time set in the **For** field has finished before firing. |
| Ok | Sets alert rule state to `Normal`. |
If your evaluation returns an error, you can set the state on your alert rule to appear as follows:
| Error | Creates an alert instance `DatasourceError` with the name and UID of the alert rule, and UID of the datasource that returned no data as labels. |
| Alerting | Sets alert rule state to `Alerting`. The alert rule waits until the time set in the **For** field has finished before firing. |
