Updating and deleting stacks in AWS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the AWS CLI command to update a CloudFormation stack named 'MyStack'.

AWS

aws cloudformation update-stack --stack-name [1] --template-body file://template.yaml

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

AMyStack

BNewStack

CStackUpdate

DOldStack

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different stack name that does not exist.

Forgetting to specify the stack name.

The --stack-name option specifies the name of the stack to update. Here, it should be 'MyStack'.

2fill in blank

medium

Complete the AWS CLI command to delete a CloudFormation stack named 'TestStack'.

AWS

aws cloudformation [1] --stack-name TestStack

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

Acreate-stack

Bupdate-stack

Cdelete-stack

Ddescribe-stacks

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'update-stack' instead of 'delete-stack'.

Confusing 'describe-stacks' with delete operation.

The delete-stack command removes the specified CloudFormation stack and all its resources.

3fill in blank

hard

Fix the error in the AWS CLI command to update a stack with a new template file named 'new-template.yaml'.

AWS

aws cloudformation update-stack --stack-name MyStack --template-body file://[1]

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

Anew-template.yaml

Bold-template.yaml

Ctemplate.yaml

Dtemplate.txt

Attempts:

3 left

💡 Hint

Common Mistakes

Using the old template file name instead of the new one.

Using a file with wrong extension.

The --template-body option must point to the correct new template file. Here, it should be 'new-template.yaml'.

4fill in blank

hard

Fill both blanks to complete the AWS CLI command that updates a stack named 'ProdStack' with a template file and a parameter override.

AWS

aws cloudformation update-stack --stack-name [1] --template-body file://[2] --parameters ParameterKey=InstanceType,ParameterValue=t2.micro

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

AProdStack

BDevStack

Cprod-template.yaml

Ddev-template.yaml

Attempts:

3 left

💡 Hint

Common Mistakes

Using development stack name with production template.

Swapping template files between environments.

The stack name is 'ProdStack' and the template file is 'prod-template.yaml' to match the production environment.

5fill in blank

hard

Fill all three blanks to complete the AWS CLI command that deletes a stack named 'TestStack' and waits until the deletion is complete.

AWS

aws cloudformation [1] --stack-name [2] && aws cloudformation wait [3] --stack-name TestStack

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

Adelete-stack

BTestStack

Cstack-delete-complete

Dupdate-stack

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'update-stack' instead of 'delete-stack'.

Using wrong wait condition like 'stack-update-complete'.

The command deletes the stack 'TestStack' and then waits until the stack deletion is complete using 'stack-delete-complete'.

Practice

1. What is the primary purpose of the update-stack command in AWS CloudFormation?

easy

A. To create a new stack from a template

B. To safely change existing cloud resources managed by a stack

C. To delete all resources created by a stack

D. To list all stacks in your AWS account

Solution

1. Step 1: Understand the role of update-stack

   The update-stack command is used to modify resources that are already managed by an existing CloudFormation stack.

2. Step 2: Differentiate from other commands

   Unlike delete-stack which removes resources, update-stack changes them safely without deleting the stack.

3. Final Answer:

   To safely change existing cloud resources managed by a stack -> Option B

4. Quick Check:

   update-stack = change resources safely [OK]

Hint: Update-stack changes resources; delete-stack removes them [OK]

Common Mistakes:

• Confusing update-stack with delete-stack
• Thinking update-stack creates new stacks
• Assuming update-stack lists stacks

2. Which AWS CLI command syntax correctly deletes a stack named MyAppStack?

easy

A. aws cloudformation delete-stack --stack-name MyAppStack

B. aws cloudformation update-stack --stack-name MyAppStack

C. aws cloudformation remove-stack --name MyAppStack

D. aws cloudformation destroy-stack --stack MyAppStack

Solution

1. Step 1: Identify the correct delete command

   The correct AWS CLI command to delete a stack is delete-stack with the parameter --stack-name.

2. Step 2: Verify syntax correctness

   aws cloudformation delete-stack --stack-name MyAppStack uses the exact syntax: aws cloudformation delete-stack --stack-name MyAppStack, which is valid and deployable.

3. Final Answer:

   aws cloudformation delete-stack --stack-name MyAppStack -> Option A

4. Quick Check:

   delete-stack + --stack-name = correct syntax [OK]

Hint: Delete stacks with 'delete-stack' and '--stack-name' [OK]

Common Mistakes:

• Using update-stack instead of delete-stack
• Wrong parameter names like --name or --stack
• Using non-existent commands like remove-stack or destroy-stack

3. Given this AWS CLI command sequence:

aws cloudformation update-stack --stack-name TestStack --template-body file://template.json
aws cloudformation describe-stacks --stack-name TestStack

What is the expected behavior after running these commands?

medium

A. The stack TestStack is updated with the new template, and its status is shown

B. The stack TestStack is deleted, and no status is returned

C. A new stack named TestStack is created, and its details are displayed

D. The command fails because update-stack cannot be followed by describe-stacks

Solution

1. Step 1: Understand update-stack effect

   The update-stack command modifies the existing stack named TestStack using the provided template.

2. Step 2: Describe-stacks shows current stack status

   The describe-stacks command retrieves details about TestStack, including its updated status.

3. Final Answer:

   The stack TestStack is updated with the new template, and its status is shown -> Option A

4. Quick Check:

   update-stack changes stack + describe-stacks shows status [OK]

Hint: Update then describe shows updated stack status [OK]

Common Mistakes:

• Thinking update-stack deletes the stack
• Assuming describe-stacks creates a new stack
• Believing update-stack and describe-stacks cannot be used sequentially

4. You run aws cloudformation update-stack --stack-name ProdStack --template-body file://newtemplate.json but get an error saying the stack is in UPDATE_IN_PROGRESS state. What should you do to fix this?

medium

A. Ignore the error and rerun update-stack multiple times

B. Run delete-stack immediately to remove the stack

C. Change the stack name and try update-stack again

D. Wait for the current update to finish before running update-stack again

Solution

1. Step 1: Understand stack states during update

   When a stack is in UPDATE_IN_PROGRESS, it means an update is already running and must complete before another update starts.

2. Step 2: Choose the correct action

   Waiting for the current update to finish avoids conflicts and errors. Deleting or renaming the stack is unnecessary and may cause data loss or confusion.

3. Final Answer:

   Wait for the current update to finish before running update-stack again -> Option D

4. Quick Check:

   UPDATE_IN_PROGRESS means wait before next update [OK]

Hint: Wait for update to finish before next update [OK]

Common Mistakes:

• Trying to delete stack during update
• Renaming stack instead of waiting
• Ignoring error and retrying immediately

5. You want to update a stack but also ensure that if the update fails, the stack rolls back to its previous state automatically. Which AWS CloudFormation option should you avoid using with update-stack to achieve this?

hard

A. --rollback-configuration

B. --no-rollback

C. --disable-rollback

D. --enable-rollback

Solution

1. Step 1: Understand rollback behavior in update-stack

   By default, CloudFormation rolls back stack updates on failure. The --disable-rollback option disables this behavior.

2. Step 2: Identify the correct option to keep rollback enabled

   To ensure rollback happens automatically on failure, you should NOT disable rollback. Therefore, do not use --disable-rollback. The default behavior is rollback enabled, so omit this option or explicitly avoid disabling rollback.

3. Step 3: Analyze options

   --rollback-configuration is for configuring alarms, --enable-rollback and --no-rollback are not valid AWS CLI options.

4. Final Answer:

   --disable-rollback disables rollback; omit it to keep rollback enabled -> Option C

5. Quick Check:

   Omit --disable-rollback to keep rollback on failure [OK]

Hint: Do not use --disable-rollback to keep rollback active [OK]

Common Mistakes:

• Using non-existent --enable-rollback option
• Confusing disable-rollback disables rollback
• Assuming rollback is off by default