Define a folder and alert rule group

Alert rules in Grafana live inside folders. You’ll create a folder first, then define a rule group inside it. A rule group is a named collection of related alert rules that share the same evaluation interval.

To define a folder and rule group, complete the following steps:

1. Create a file named alerts.tf with a folder and rule group:

   hcl Copy

   resource "grafana_folder" "alerts" {
     title = "Terraform Alerts"
   }
   
   resource "grafana_rule_group" "cpu_alerts" {
     name             = "CPU alerts"
     folder_uid       = grafana_folder.alerts.uid
     interval_seconds = 60
   
     rule {
       name      = "High CPU usage"
       condition = "C"
       for       = "5m"
   
       data {
         ref_id         = "A"
         datasource_uid = "<YOUR_DATASOURCE_UID>"
   
         relative_time_range {
           from = 600
           to   = 0
         }
   
         model = jsonencode({
           expr = "100 - (avg(rate(node_cpu_seconds_total{mode=\"idle\"}[5m])) * 100)"
         })
       }
   
       data {
         ref_id         = "B"
         datasource_uid = "__expr__"
   
         relative_time_range {
           from = 0
           to   = 0
         }
   
         model = jsonencode({
           type       = "reduce"
           expression = "A"
           reducer    = "last"
         })
       }
   
       data {
         ref_id         = "C"
         datasource_uid = "__expr__"
   
         relative_time_range {
           from = 0
           to   = 0
         }
   
         model = jsonencode({
           type       = "threshold"
           expression = "B"
           conditions = [{
             evaluator = {
               type   = "gt"
               params = [80]
             }
           }]
         })
       }
   
       labels = {
         severity = "warning"
       }
   
       annotations = {
         summary     = "CPU usage is above 80%"
         description = "CPU usage has been above 80% for 5 minutes."
       }
     }
   }

2. Replace <YOUR_DATASOURCE_UID> with the UID of a Prometheus data source in your Grafana instance. You can find the UID in Grafana under Connections > Data sources, then click your data source and note the UID from the URL or the settings page.

Note: If you don’t have a Prometheus data source, you can use grafana-testdata-datasource as the datasource_uid and adjust the query model to use TestData expressions instead.

How the data blocks work

The three data blocks form a query pipeline:

The condition = "C" on the rule tells Grafana which data block determines when the alert fires.

In the next milestone, you add a contact point to receive alert notifications.