Terraform destroy for cleanup - Mini Project: Build & Apply

Terraform destroy for cleanup

📖 Scenario: You have created a simple cloud infrastructure using Terraform. Now, you want to learn how to clean up and remove all the resources you created to avoid extra costs.

🎯 Goal: Learn how to write a Terraform configuration for a basic resource and then use terraform destroy to clean up the resources safely.

📋 What You'll Learn

Create a Terraform configuration file with a simple resource

Initialize Terraform in the project directory

Apply the Terraform configuration to create the resource

Use terraform destroy to remove the resource

💡 Why This Matters

🌍 Real World

Cloud engineers often create resources for testing or development. Cleaning up with <code>terraform destroy</code> helps avoid unnecessary costs and keeps the cloud environment tidy.

💼 Career

Knowing how to safely create and destroy infrastructure with Terraform is essential for cloud infrastructure management roles.

1

Create a Terraform configuration with an AWS S3 bucket

Create a file named main.tf and write a Terraform configuration that defines an AWS S3 bucket resource named my_bucket with the bucket name my-unique-bucket-12345. Use the AWS provider with region us-east-1.

Terraform

# Write the Terraform provider and resource configuration here
# Your code here

Hint

Start by declaring the AWS provider with the region us-east-1. Then define an S3 bucket resource with the exact name my_bucket and bucket name my-unique-bucket-12345.

2

Initialize Terraform in the project directory

Write the Terraform CLI command to initialize the Terraform working directory so that the AWS provider plugin is downloaded and ready.

Terraform

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.0"
    }
  }
}

provider "aws" {
  region = "us-east-1"
}

resource "aws_s3_bucket" "my_bucket" {
  bucket = "my-unique-bucket-12345"
  acl    = "private"
}

# Write the command to initialize Terraform below
# Your code here

Hint

Use the command terraform init to prepare your working directory.

3

Apply the Terraform configuration to create the S3 bucket

Write the Terraform CLI command to apply the configuration and create the S3 bucket resource. Use the -auto-approve flag to skip manual approval.

Terraform

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.0"
    }
  }
}

provider "aws" {
  region = "us-east-1"
}

resource "aws_s3_bucket" "my_bucket" {
  bucket = "my-unique-bucket-12345"
  acl    = "private"
}

# terraform init
# Write the command to apply the configuration below
# Your code here

Hint

Use terraform apply -auto-approve to create the resources without manual confirmation.

4

Destroy the Terraform-managed infrastructure to clean up

Write the Terraform CLI command to destroy all the resources created by Terraform. Use the -auto-approve flag to skip manual approval.

Terraform

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.0"
    }
  }
}

provider "aws" {
  region = "us-east-1"
}

resource "aws_s3_bucket" "my_bucket" {
  bucket = "my-unique-bucket-12345"
  acl    = "private"
}

# terraform init
# terraform apply -auto-approve
# Write the command to destroy the infrastructure below
# Your code here

Hint

Use terraform destroy -auto-approve to remove all resources without manual confirmation.

Practice

1. What does the terraform destroy command do?

easy

A. It updates existing resources without deleting them.

B. It deletes all resources created by Terraform in the current workspace.

C. It creates new resources defined in the configuration.

D. It shows the current state of resources without making changes.

Solution

1. Step 1: Understand the purpose of terraform destroy

   This command is designed to remove all resources that Terraform manages in the current workspace. Unlike terraform apply which creates or updates resources, terraform destroy deletes them. It does not just show state or update resources.

2. Final Answer:

   It deletes all resources created by Terraform in the current workspace. -> Option B

3. Quick Check:

   terraform destroy = deletes resources [OK]

Hint: Destroy means delete all created resources [OK]

Common Mistakes:

• Confusing destroy with apply
• Thinking destroy only shows resources
• Assuming destroy updates resources

2. Which of the following is the correct syntax to run terraform destroy without asking for confirmation?

easy

A. terraform destroy -force

B. terraform destroy --yes

C. terraform destroy --confirm

D. terraform destroy -auto-approve

Solution

1. Step 1: Recall the flag to skip confirmation

   The correct flag to skip the confirmation prompt is -auto-approve. -force, --yes, and --confirm are not valid flags for terraform destroy.

2. Final Answer:

   terraform destroy -auto-approve -> Option D

3. Quick Check:

   Skip confirmation = -auto-approve [OK]

Hint: Use -auto-approve to skip confirmation [OK]

Common Mistakes:

• Using -force instead of -auto-approve
• Typing --yes which is invalid
• Assuming --confirm works

3. Given the following Terraform commands run in order:
terraform apply -auto-approve
terraform destroy
What will happen after the second command?

medium

A. All resources created by the first command will be deleted after confirmation.

B. Resources will be updated but not deleted.

C. Nothing will happen because destroy requires -auto-approve.

D. Terraform will show an error because destroy must be run before apply.

Solution

1. Step 1: Understand the effect of terraform apply -auto-approve

   This command creates or updates resources without asking for confirmation. This command will prompt for confirmation before deleting all resources created by Terraform.

2. Final Answer:

   All resources created by the first command will be deleted after confirmation. -> Option A

3. Quick Check:

   Destroy deletes resources after confirmation [OK]

Hint: Destroy deletes resources after confirmation unless skipped [OK]

Common Mistakes:

• Thinking destroy needs -auto-approve to work
• Believing destroy updates resources
• Assuming destroy must run before apply

4. You ran terraform destroy but it failed with an error about a locked state file. What should you do to fix this?

medium

A. Run terraform init again to reset the state.

B. Manually delete the state file from your local machine.

C. Use terraform force-unlock with the lock ID to unlock the state.

D. Delete all resources manually in the cloud provider console.

Solution

1. Step 1: Understand state locking in Terraform

   Terraform locks the state file during operations to prevent conflicts. If locked, commands like destroy fail. terraform force-unlock with the lock ID safely removes the lock so you can continue.

2. Final Answer:

   Use terraform force-unlock with the lock ID to unlock the state. -> Option C

3. Quick Check:

   Unlock state with force-unlock command [OK]

Hint: Use terraform force-unlock to fix locked state errors [OK]

Common Mistakes:

• Deleting state file manually causing data loss
• Running terraform init which doesn't unlock state
• Manually deleting cloud resources instead of fixing state

5. You want to automate cleanup of your test environment using Terraform. Which approach safely destroys all resources without manual confirmation and logs the output to a file?

hard

A. Run terraform destroy -auto-approve > destroy.log to skip confirmation and save output.

B. Run terraform apply -destroy -auto-approve to destroy and log output automatically.

C. Run terraform destroy --force --log=destroy.log to force destroy and log output.

D. Run terraform delete -auto-approve > destroy.log to delete resources and log output.

Solution

1. Step 1: Identify correct command to destroy without confirmation

   terraform destroy -auto-approve skips confirmation safely. Using shell redirection with > destroy.log saves the command output to a log file.

2. Final Answer:

   Run terraform destroy -auto-approve > destroy.log to skip confirmation and save output. -> Option A

3. Quick Check:

   Destroy + auto-approve + output redirection = Run terraform destroy -auto-approve > destroy.log to skip confirmation and save output. [OK]

Hint: Use -auto-approve and > file to automate and log destroy [OK]

Common Mistakes:

• Using invalid flags like --force or --log
• Confusing apply with destroy for cleanup
• Using terraform delete which is not a valid command