Apply and verify

With the plan confirmed, you can now apply it to deploy your alerting pipeline to Grafana.

To deploy and verify your alerting pipeline, complete the following steps:

1. Run terraform apply:

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   terraform apply

2. Terraform displays the plan again and asks for confirmation. Type yes and press Enter:

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   Do you want to perform these actions?
     Terraform will perform the actions described above.
     Only 'yes' will be accepted to approve.
   
     Enter a value: yes

3. Wait for Terraform to complete. You should see:

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   Apply complete! Resources: 4 added, 0 changed, 0 destroyed.

4. Open your Grafana instance in a browser and navigate to Alerting > Alert rules in the left-side menu.

5. Look for the Terraform Alerts folder. Click into it.

6. Confirm the CPU alerts rule group appears with the High CPU usage rule.

7. Navigate to Alerting > Contact points and confirm Email alerts appears.

8. Navigate to Alerting > Notification policies and confirm the default route points to your contact point.

Updating a deployed alert rule

When you modify your HCL and run terraform apply again, Terraform detects the change and updates the existing resources in place. No duplicates, no manual intervention.

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# After modifying alerts.tf:
terraform plan    # Preview the update
terraform apply   # Apply the update

What Terraform state tracks

Terraform stores the deployed resource IDs in its state file (terraform.tfstate). This is how it knows whether to create or update a resource on subsequent runs. Keep the state file safe. If you lose it, Terraform won’t know about existing resources.

Your alerting pipeline is now deployed and managed by Terraform.