Terraform Lifecycle Meta-Argument

Terraform’s lifecycle meta-argument helps control how resources are created, updated, and destroyed. It includes:

• create_before_destroy – Ensures a new resource is created before deleting the old one, preventing downtime.
• prevent_destroy – Blocks accidental deletions of critical resources.
• ignore_changes – Ignores changes to specific attributes that might be modified outside Terraform.
• triggered_by – Ensures that a resource is recreated (destroyed and recreated) when specific referenced resources or variables change.

Create a Directory for Your Terraform Files

Create a main.tf File

Define the Azure Provider in main.tf

Initialize Terraform

Plan Terraform Deployment

Apply Terraform Configuration

Task 1: Create Before Destroy

• Edit the main.tf file and change the name of the Storage Account to lifecyclegroupstorage1.
• Apply the changes:

• Notice that first, the destroy is triggered, and then the creation.
• Uncomment the lifecycle rule

• Apply again:

• Notice that first, the create is triggered, and then the destroy.

Task 2: Prevent Destroy

• Comment out create_before_destroy and uncomment prevent_destroy.
• Attempt to destroy the resources:

• Terraform will not destroy this resource, even when you run terraform destroy. Any attempt to destroy it will result in an error.

Task 3: Ignore Changes

• Edit the main.tf file:
  • Change the name of the Storage Account to lifecyclegroupstorage2.
  • Uncomment ignore_changes.
  • Comment prevent_destroy.
• Apply the changes:

• Notice that no change will be done.

Task 4: Replace Triggered By

• Edit the main.tf file:
  • Change the name of the Storage Account from triggeringresource to triggeringresource1.
  • Comment ignore_changes.
  • Uncomment replace_triggered_by.
• Apply the changes:

• Notice that although we have made no changes to lifecyclegroupstorage, it is also being destroyed and recreated.

Cleanup

About CloudThat