Creation-time vs destruction-time in Terraform - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a resource that creates an AWS S3 bucket.

Terraform

resource "aws_s3_bucket" "my_bucket" {
  bucket = "[1]"
  acl    = "private"
}

Drag options to blanks, or click blank then click option'

Abucket_name

Baws_s3_bucket

Cmy-unique-bucket-123

Dprivate

Attempts:

3 left

💡 Hint

Common Mistakes

Using resource type name instead of bucket name

Using ACL value in bucket name field

The bucket attribute requires the unique name of the S3 bucket to create at creation-time.

2fill in blank

medium

Complete the code to add a lifecycle rule that prevents deletion of the S3 bucket during destruction-time.

Terraform

resource "aws_s3_bucket" "my_bucket" {
  bucket = "my-unique-bucket-123"
  acl    = "private"

  lifecycle {
    [1] = true
  }
}

Drag options to blanks, or click blank then click option'

Aprevent_destroy

Bcreate_before_destroy

Cignore_changes

Dreplace_triggered_by

Attempts:

3 left

💡 Hint

Common Mistakes

Using lifecycle arguments unrelated to destruction protection

Setting the wrong lifecycle argument name

The prevent_destroy lifecycle argument tells Terraform to block destruction of the resource, protecting it during destruction-time.

3fill in blank

hard

Fix the error in the code that tries to reference a resource attribute at destruction-time, which is not allowed.

Terraform

output "bucket_name" {
  value = aws_s3_bucket.my_bucket.[1]
}

Drag options to blanks, or click blank then click option'

Atags

Barn

Cid

Dbucket

Attempts:

3 left

💡 Hint

Common Mistakes

Referencing attributes that only exist after creation

Using resource IDs that may be null during destruction

The bucket attribute is the bucket name known at creation-time and can be safely referenced. Other attributes like id or arn may not be available during destruction-time.

4fill in blank

hard

Fill both blanks to create a resource with a creation-time computed attribute and a destruction-time lifecycle rule.

Terraform

resource "aws_instance" "example" {
  ami           = "ami-12345678"
  instance_type = "t2.micro"

  [1] = true

  lifecycle {
    [2] = true
  }
}

Drag options to blanks, or click blank then click option'

Aassociate_public_ip_address

Bprevent_destroy

Cdisable_api_termination

Dcreate_before_destroy

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing lifecycle arguments with resource arguments

Using wrong lifecycle argument names

disable_api_termination is a creation-time attribute that prevents instance termination via API. prevent_destroy is a lifecycle rule that prevents Terraform from destroying the resource.

5fill in blank

hard

Fill all three blanks to define an output that depends on a creation-time attribute, uses a destruction-time lifecycle ignore change, and references the correct attribute.

Terraform

resource "aws_security_group" "sg" {
  name        = "example-sg"
  description = "Example security group"

  lifecycle {
    [1] = ["ingress"]
  }
}

output "sg_id" {
  value = aws_security_group.sg.[2]
  description = "Security group ID"
  depends_on = [aws_security_group.sg]
  [3] = true
}

Drag options to blanks, or click blank then click option'

Aignore_changes

Bid

Csensitive

Dprevent_destroy

Attempts:

3 left

💡 Hint

Common Mistakes

Using prevent_destroy in output block

Referencing attributes not available at creation-time

Not marking sensitive outputs when needed

ignore_changes lifecycle argument tells Terraform to ignore changes to ingress rules during destruction-time. The output references the id attribute, which is known at creation-time. The output is marked sensitive to hide its value in logs.

Practice

1. What does creation-time mean in Terraform?

easy

A. The moment when resources are first set up or created

B. The moment when resources are deleted or removed

C. The time when Terraform runs a plan without changes

D. The time when Terraform refreshes the state

Solution

1. Step 1: Understand creation-time meaning

   Creation-time refers to when Terraform sets up resources for the first time.

2. Step 2: Differentiate from destruction-time

   Destruction-time is when resources are removed, not created.

3. Final Answer:

   The moment when resources are first set up or created -> Option A

4. Quick Check:

   Creation-time = resource setup [OK]

Hint: Creation-time means resource setup, destruction-time means removal [OK]

Common Mistakes:

• Confusing creation-time with destruction-time
• Thinking creation-time is when resources are deleted
• Mixing creation-time with Terraform plan execution

2. Which Terraform lifecycle argument controls actions at destruction-time?

easy

A. create_before_destroy

B. depends_on

C. ignore_changes

D. prevent_destroy

Solution

1. Step 1: Identify destruction-time control arguments

   The prevent_destroy argument stops Terraform from deleting a resource.

2. Step 2: Compare other lifecycle arguments

   create_before_destroy affects creation and replacement order, not destruction prevention.

3. Final Answer:

   prevent_destroy -> Option D

4. Quick Check:

   Destruction-time control = prevent_destroy [OK]

Hint: Use prevent_destroy to block resource deletion at destruction-time [OK]

Common Mistakes:

• Choosing create_before_destroy which affects creation order
• Confusing ignore_changes with destruction control
• Using depends_on which manages resource dependencies

3. Given this Terraform snippet:

resource "aws_instance" "example" {
  ami           = "ami-123456"
  instance_type = "t2.micro"

  lifecycle {
    create_before_destroy = true
  }
}

What happens when you change instance_type from t2.micro to t2.small?

medium

A. Terraform destroys the old instance first, then creates the new one

B. Terraform updates the instance in place without destruction

C. Terraform creates the new instance first, then destroys the old one

D. Terraform throws an error due to lifecycle conflict

Solution

1. Step 1: Understand create_before_destroy effect

   This setting makes Terraform create the new resource before destroying the old one.

2. Step 2: Apply to instance_type change

   Changing instance_type forces replacement, so new instance is created first, then old destroyed.

3. Final Answer:

   Terraform creates the new instance first, then destroys the old one -> Option C

4. Quick Check:

   create_before_destroy = new before old [OK]

Hint: create_before_destroy means new resource before old is removed [OK]

Common Mistakes:

• Assuming in-place update without replacement
• Thinking old resource is destroyed before new is created
• Believing lifecycle causes errors on changes

4. You added prevent_destroy = true to a resource but Terraform still deletes it on terraform destroy. What is the likely cause?

medium

A. You ran terraform destroy which ignores prevent_destroy

B. The prevent_destroy argument is misspelled or misplaced

C. The resource is referenced by another resource with depends_on

D. Terraform does not support prevent_destroy for that resource type

Solution

1. Step 1: Check prevent_destroy usage

   It must be inside the lifecycle block and spelled correctly.

2. Step 2: Understand terraform destroy behavior

   terraform destroy respects prevent_destroy and will error if deletion is blocked.

3. Final Answer:

   The prevent_destroy argument is misspelled or misplaced -> Option B

4. Quick Check:

   Misplaced prevent_destroy causes deletion despite protection [OK]

Hint: Ensure prevent_destroy is inside lifecycle block and spelled right [OK]

Common Mistakes:

• Assuming terraform destroy ignores prevent_destroy
• Placing prevent_destroy outside lifecycle block
• Thinking depends_on affects prevent_destroy behavior

5. You want to replace a resource safely without downtime. Which lifecycle settings should you use to ensure the new resource is created before the old one is destroyed, and prevent accidental deletion?

hard

A. Set create_before_destroy = true and prevent_destroy = true

B. Set create_before_destroy = false and prevent_destroy = true

C. Set create_before_destroy = true and ignore_changes = [all]

D. Set prevent_destroy = false and ignore_changes = [all]

Solution

1. Step 1: Use create_before_destroy for safe replacement

   This ensures the new resource is ready before the old one is removed, avoiding downtime.

2. Step 2: Use prevent_destroy to block accidental deletion

   This stops Terraform from deleting the resource unless explicitly allowed, adding safety.

3. Final Answer:

   Set create_before_destroy = true and prevent_destroy = true -> Option A

4. Quick Check:

   Safe replacement = create_before_destroy + prevent_destroy [OK]

Hint: Combine create_before_destroy and prevent_destroy for safe updates [OK]

Common Mistakes:

• Setting prevent_destroy without create_before_destroy causes downtime
• Using ignore_changes to avoid destruction which doesn't prevent deletion
• Disabling prevent_destroy risks accidental resource loss