Drift detection in CI/CD in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize Terraform before running drift detection.

Terraform

terraform [1]

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

Ainit

Bapply

Cplan

Ddestroy

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'apply' before initialization causes errors.

Confusing 'plan' with initialization.

Terraform must be initialized with terraform init to set up the backend and providers before any plan or apply commands.

2fill in blank

medium

Complete the code to create a Terraform plan that detects drift without applying changes.

Terraform

terraform [1] -detailed-exitcode

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

Avalidate

Bapply

Cplan

Ddestroy

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'apply' applies changes instead of detecting drift.

Using 'destroy' removes resources, not detecting drift.

The terraform plan command shows changes without applying them. The -detailed-exitcode flag helps detect drift by returning specific exit codes.

3fill in blank

hard

Fix the error in the command to detect drift by returning a detailed exit code.

Terraform

terraform plan [1] -detailed-exitcode

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

A-auto-approve

B-refresh=true

C-refresh=false

D-input=false

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-refresh=false' disables state refresh, missing drift.

Using '-auto-approve' is for apply, not plan.

The -refresh=true flag ensures Terraform refreshes the state from real infrastructure, which is necessary for accurate drift detection.

4fill in blank

hard

Fill both blanks to create a CI/CD step that runs drift detection and fails if drift is found.

Terraform

terraform [1] -detailed-exitcode || exit [2]

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

Aplan

Bapply

C1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'apply' applies changes instead of detecting drift.

Exiting with 0 means success even if drift exists.

The command runs terraform plan with detailed exit codes. If drift is detected, it exits with code 1 to fail the CI/CD step.

5fill in blank

hard

Fill all three blanks to define a Terraform workflow step that initializes, refreshes state, and detects drift.

Terraform

terraform [1] && terraform plan [2] -detailed-exitcode || exit [3]

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

Ainit

B-refresh=true

C1

D-auto-approve

Attempts:

3 left

💡 Hint

Common Mistakes

Skipping initialization causes errors.

Not refreshing state misses drift detection.

Exiting with 0 ignores drift.

This sequence initializes Terraform, refreshes the state during plan to detect drift, and exits with code 1 if drift is found, causing CI/CD failure.

Practice

1. What is the main purpose of drift detection in a Terraform CI/CD pipeline?

easy

A. To find differences between the Terraform code and the actual infrastructure

B. To speed up the deployment process by skipping validation

C. To automatically delete unused resources without approval

D. To generate documentation for the infrastructure

Solution

1. Step 1: Understand drift detection concept

   Drift detection compares the current real infrastructure state with the Terraform code to find differences.

2. Step 2: Identify the purpose in CI/CD

   In CI/CD, drift detection helps catch unexpected changes before applying new updates.

3. Final Answer:

   To find differences between the Terraform code and the actual infrastructure -> Option A

4. Quick Check:

   Drift detection = find differences [OK]

Hint: Drift detection = spot differences before apply [OK]

Common Mistakes:

• Thinking drift detection speeds deployment
• Assuming it deletes resources automatically
• Confusing it with documentation generation

2. Which Terraform command is commonly used in CI/CD pipelines to detect drift before applying changes?

easy

A. terraform plan

B. terraform apply

C. terraform init

D. terraform destroy

Solution

1. Step 1: Recall Terraform commands

   terraform plan shows the changes Terraform will make without applying them.

2. Step 2: Identify drift detection command

   terraform plan detects differences (drift) between code and real infrastructure before apply.

3. Final Answer:

   terraform plan -> Option A

4. Quick Check:

   Detect drift = terraform plan [OK]

Hint: Use terraform plan to preview changes [OK]

Common Mistakes:

• Using terraform apply which changes infrastructure
• Confusing terraform init with drift detection
• Using terraform destroy which deletes resources

3. Given the following Terraform plan output snippet in a CI/CD pipeline:

  # aws_instance.example will be updated in-place
  ~ tags = {
      - "Environment" = "dev"
      + "Environment" = "prod"
    }

What does this output indicate about drift?

medium

A. Terraform will ignore the tag change

B. The instance will be destroyed and recreated

C. No drift is detected; tags remain unchanged

D. The tag "Environment" has drifted from "dev" to "prod" and will be updated

Solution

1. Step 1: Analyze the plan output

   The '~' symbol means in-place update. The tag "Environment" changes from "dev" to "prod".

2. Step 2: Understand drift implication

   This shows drift: the real infrastructure tag differs from code and will be updated.

3. Final Answer:

   The tag "Environment" has drifted from "dev" to "prod" and will be updated -> Option D

4. Quick Check:

   ~ means update tag from dev to prod [OK]

Hint: Look for ~ symbol to spot in-place updates [OK]

Common Mistakes:

• Thinking resource will be destroyed instead of updated
• Ignoring tag changes as no drift
• Assuming Terraform ignores tag differences

4. You run terraform plan in your CI/CD pipeline but it does not detect drift even though manual changes were made outside Terraform. What is the most likely cause?

medium

A. Terraform automatically ignores manual changes

B. You forgot to run terraform apply first

C. Terraform state file is outdated or corrupted

D. The provider plugin is missing

Solution

1. Step 1: Understand drift detection dependency

   Terraform relies on the state file to compare real infrastructure with code.

2. Step 2: Identify cause of missed drift

   If the state file is outdated or corrupted, Terraform cannot detect manual changes (drift).

3. Final Answer:

   Terraform state file is outdated or corrupted -> Option C

4. Quick Check:

   State file outdated = missed drift detection [OK]

Hint: Check state file freshness if drift not detected [OK]

Common Mistakes:

• Assuming terraform apply affects drift detection
• Believing Terraform ignores manual changes by design
• Thinking missing provider causes drift detection failure

5. In a CI/CD pipeline, you want to automatically detect drift and fail the pipeline if any drift is found before applying changes. Which approach best achieves this?

hard

A. Run terraform apply directly and rely on errors to detect drift

B. Run terraform plan and parse its output to detect changes, then fail if changes exist

C. Skip drift detection and always apply changes

D. Manually check infrastructure outside the pipeline

Solution

1. Step 1: Understand CI/CD drift detection goal

   The goal is to detect drift and fail early before applying changes.

2. Step 2: Choose correct command and method

   terraform plan shows drift without applying; parsing its output allows pipeline to fail if drift exists.

3. Step 3: Evaluate other options

   Applying directly risks unwanted changes; manual checks are slow; skipping detection is unsafe.

4. Final Answer:

   Run terraform plan and parse its output to detect changes, then fail if changes exist -> Option B

5. Quick Check:

   Plan + parse output = fail on drift [OK]

Hint: Use terraform plan output to gate pipeline success [OK]

Common Mistakes:

• Applying without checking drift first
• Relying on manual checks in automated pipelines
• Ignoring drift detection to speed up deploys