# Recording Rules

Recording rules in Kloudfuse transform and aggregate metrics according to predefined expressions, reducing data storage and query costs. You can modify these rules by updating the configuration in your Kloudfuse file and redeploying the Helm release to apply the changes.

Periodically, you must update the recording rules for metrics. Follow these steps:

1. Add the following configuration for recording rules to the Kloudfuse `custom_values.yaml` file.

2. Change the rule name and expression as necessary.

```yaml
     rulemanager:
       rules:
         groups:
      - name: recording_rules
        rules:
          - record: application_availability_slo (1)
            expr: sum by (kube_cluster_name, kube_service) (increase(promhttp_metric_handler_requests_total{code=~"2.*"}[28d])) / sum by (kube_cluster_name, kube_service) (increase(promhttp_metric_handler_requests_total{code=~"2.*|5.*"}[28d]))
```

|     |     |
| --- | --- |
| **1** | Defines a new metric `application_availability_slo` using the rule specified in the `expr` field. |

3. If adding multiple rules, then add them to a group of its own, `MyGroup`:

```yaml
     rulemanager:
       rules:
         ...
         MyGroup:
      - name: my_group_rules
        rules:
          - record: rule_name_1
            expr: sum by (kube_cluster_name, kube_service) (increase(promhttp_metric_handler_requests_total{code=~"2.*"}[28d])) / sum by (kube_cluster_name, kube_service) (increase(promhttp_metric_handler_requests_total{code=~"2.*|5.*"}[28d]))
```

4. Reinstall the Helm release.