Stack drift detection in AWS - Mini Project: Build & Apply

Stack drift detection

📖 Scenario: You manage cloud resources using AWS CloudFormation stacks. Sometimes, manual changes happen outside CloudFormation, causing your stack to drift from its original setup. Detecting this drift helps keep your infrastructure reliable and consistent.

🎯 Goal: Build a simple AWS CloudFormation stack drift detection setup using AWS CLI commands. You will create a stack, configure drift detection, and check the drift status.

📋 What You'll Learn

Create a CloudFormation stack named MyTestStack with a simple resource

Configure drift detection for the stack

Detect drift on the stack using AWS CLI

Check and output the drift detection status

💡 Why This Matters

🌍 Real World

Cloud engineers use stack drift detection to ensure infrastructure matches the declared configuration, preventing unexpected issues.

💼 Career

Understanding stack drift detection is essential for roles in cloud operations, DevOps, and infrastructure management to maintain reliable cloud environments.

1

Create a CloudFormation stack named MyTestStack

Use the AWS CLI command aws cloudformation create-stack to create a stack named MyTestStack with a simple template that creates an S3 bucket named my-test-bucket-12345.

AWS

# Use AWS CLI to create the stack
# Your code here

Hint

Use a JSON template inline with --template-body to define the S3 bucket resource.

2

Start drift detection on the stack MyTestStack

Use the AWS CLI command aws cloudformation detect-stack-drift with the stack name MyTestStack to start drift detection.

AWS

aws cloudformation create-stack --stack-name MyTestStack --template-body '{"Resources":{"MyBucket":{"Type":"AWS::S3::Bucket","Properties":{"BucketName":"my-test-bucket-12345"}}}}'
# Start drift detection on MyTestStack
# Your code here

Hint

Use detect-stack-drift with the exact stack name to start detection.

3

Check the drift detection status for MyTestStack

Use the AWS CLI command aws cloudformation describe-stack-drift-detection-status with the StackDriftDetectionId returned from the previous step to check the drift detection status.

AWS

aws cloudformation detect-stack-drift --stack-name MyTestStack
# Use describe-stack-drift-detection-status with the detection ID
# Your code here

Hint

Replace <StackDriftDetectionId> with the actual ID from the detect-stack-drift command output.

4

Retrieve and display the drift status of MyTestStack

Use the AWS CLI command aws cloudformation describe-stack-resource-drifts with the stack name MyTestStack to get detailed drift information about each resource.

AWS

aws cloudformation describe-stack-drift-detection-status --stack-drift-detection-id 
# Get detailed resource drift info for MyTestStack
# Your code here

Hint

This command shows which resources have drifted and how.

Practice

1.

What is the main purpose of stack drift detection in AWS CloudFormation?

easy

A. To find manual changes made outside of CloudFormation templates

B. To automatically fix errors in CloudFormation templates

C. To create new stacks from existing templates

D. To monitor network traffic between AWS resources

Solution

1. Step 1: Understand stack drift detection concept

   Stack drift detection checks if resources in a stack have been changed manually or outside CloudFormation management.

2. Step 2: Identify the main purpose

   The main goal is to find these manual or unexpected changes to keep infrastructure consistent.

3. Final Answer:

   To find manual changes made outside of CloudFormation templates -> Option A

4. Quick Check:

   Stack drift detection = find manual changes [OK]

Hint: Stack drift detection finds changes outside CloudFormation [OK]

Common Mistakes:

• Thinking it fixes errors automatically
• Confusing it with stack creation
• Assuming it monitors network traffic

2.

Which AWS CLI command starts drift detection for a CloudFormation stack named MyAppStack?

easy

A. aws cloudformation begin-drift-check --name MyAppStack

B. aws cloudformation detect-stack-drift --stack-name MyAppStack

C. aws cloudformation start-drift-detection --stack MyAppStack

D. aws cloudformation check-drift --stack-name MyAppStack

Solution

1. Step 1: Recall AWS CLI syntax for drift detection

   The correct command to start drift detection is detect-stack-drift with the --stack-name option.

2. Step 2: Match the command with the stack name

   aws cloudformation detect-stack-drift --stack-name MyAppStack uses the exact syntax and correct parameter for the stack name.

3. Final Answer:

   aws cloudformation detect-stack-drift --stack-name MyAppStack -> Option B

4. Quick Check:

   Detect drift command = detect-stack-drift [OK]

Hint: Use 'detect-stack-drift' with '--stack-name' to start detection [OK]

Common Mistakes:

• Using incorrect command verbs like start or begin
• Wrong parameter names like --stack or --name
• Mixing up command order or syntax

3.

After running aws cloudformation detect-stack-drift --stack-name MyStack, which command shows the drift detection status and results?

medium

A. aws cloudformation show-drift-results --stack-name MyStack

B. aws cloudformation get-stack-drift-status --stack-name MyStack

C. aws cloudformation list-stack-drift-detection --stack-name MyStack

D. aws cloudformation describe-stack-drift-detection-status --stack-drift-detection-id

Solution

1. Step 1: Identify the command to check drift detection status

   The AWS CLI command to check drift detection status is describe-stack-drift-detection-status.

2. Step 2: Confirm the correct parameter usage

   It requires the --stack-drift-detection-id parameter to specify the detection ID, not --stack-name.

3. Final Answer:

   aws cloudformation describe-stack-drift-detection-status --stack-drift-detection-id <detection-id> -> Option D

4. Quick Check:

   Check drift status = describe-stack-drift-detection-status [OK]

Hint: Use 'describe-stack-drift-detection-status' with detection ID to get drift results [OK]

Common Mistakes:

• Using non-existent commands like get-stack-drift-status
• Confusing list commands with status commands
• Wrong parameter names

4.

You ran aws cloudformation detect-stack-drift --stack-name TestStack but got an error: Stack with id TestStack does not exist. What is the most likely cause?

medium

A. The stack name is misspelled or the stack does not exist

B. Drift detection is not supported for this stack type

C. You need to add --region parameter to the command

D. The AWS CLI version is outdated and cannot run drift detection

Solution

1. Step 1: Analyze the error message

   The error says the stack with the given name does not exist, indicating a wrong name or missing stack.

2. Step 2: Consider other causes

   While region or CLI version issues can cause errors, this specific message points to a missing or misspelled stack name.

3. Final Answer:

   The stack name is misspelled or the stack does not exist -> Option A

4. Quick Check:

   Error about stack id means wrong or missing stack [OK]

Hint: Check stack name spelling and existence first [OK]

Common Mistakes:

• Assuming region parameter is always required
• Blaming CLI version without checking stack
• Ignoring the exact error message

5.

You want to ensure your CloudFormation stack stays consistent with its template. Which approach best uses stack drift detection to maintain this?

A) Run drift detection regularly and update stack if drift is detected.
B) Disable drift detection and manually check resources.
C) Use drift detection only after stack deletion.
D) Ignore drift detection and rely on CloudWatch alarms.

hard

A. Use drift detection only after stack deletion

B. Disable drift detection and manually check resources

C. Run drift detection regularly and update stack if drift is detected

D. Ignore drift detection and rely on CloudWatch alarms

Solution

1. Step 1: Understand drift detection best practice

   Regularly running drift detection helps find manual changes early and keeps the stack consistent.

2. Step 2: Evaluate options

   Run drift detection regularly and update stack if drift is detected uses drift detection proactively. Options B, C, and D either ignore drift detection or use it incorrectly.

3. Final Answer:

   Run drift detection regularly and update stack if drift is detected -> Option C

4. Quick Check:

   Regular drift detection = best practice [OK]

Hint: Run drift detection regularly to catch changes early [OK]

Common Mistakes:

• Ignoring drift detection completely
• Checking drift only after deletion
• Relying solely on CloudWatch for drift