# Alert instances
<a name="v12-alerting-rules-instances"></a>

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This documentation topic is designed for Grafana workspaces that support **Grafana version 12.x**.  
For Grafana workspaces that support Grafana version 10.x, see [Working in Grafana version 10](using-grafana-v10.md).  
For Grafana workspaces that support Grafana version 9.x, see [Working in Grafana version 9](using-grafana-v9.md).  
For Grafana workspaces that support Grafana version 8.x, see [Working in Grafana version 8](using-grafana-v8.md).

Grafana managed alerts support multi-dimensional alerting. Each alert rule can create multiple alert instances. This is powerful if you are observing multiple series in a single expression.

Consider the following PromQL expression:

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

A rule using this expression will create as many alert instances as the amount of CPUs we are observing after the first evaluation, allowing a single rule to report the status of each CPU.