Updating and deleting stacks in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

What happens when you update an AWS CloudFormation stack with a template that removes a resource?

You have an existing CloudFormation stack with several resources. You update the stack by uploading a new template that no longer includes one of the original resources. What is the expected behavior?

A The resource is deleted from the stack and removed from your AWS account.

B The resource remains unchanged in your AWS account but is no longer managed by the stack.

C The update fails with an error because resources cannot be removed from a stack.

D The resource is stopped but not deleted, and remains in your AWS account.

💡 Hint

Think about how CloudFormation manages resources when they are removed from the template.

When a resource is removed from a CloudFormation template during an update, CloudFormation deletes that resource from the stack and your AWS account, unless you have specified a deletion policy to retain it.

❓ Architecture

intermediate

Which AWS CloudFormation stack deletion policy prevents resource deletion when the stack is deleted?

You want to delete a CloudFormation stack but keep certain resources intact in your AWS account. Which deletion policy should you apply to those resources?

A Protect

B Snapshot

C Delete

D Retain

💡 Hint

Consider which policy tells CloudFormation to keep the resource even if the stack is deleted.

The 'Retain' deletion policy tells CloudFormation to keep the resource in your AWS account when the stack is deleted. 'Snapshot' creates a backup before deletion, 'Delete' removes the resource, and 'Protect' is not a valid deletion policy.

❓ security

advanced

What IAM permission is required to delete an AWS CloudFormation stack?

To delete a CloudFormation stack, which IAM permission must a user have?

A cloudformation:TerminateStack

B cloudformation:DeleteStack

C cloudformation:RemoveStack

D cloudformation:DestroyStack

💡 Hint

Check the exact AWS IAM action name for deleting stacks.

The correct IAM permission to delete a CloudFormation stack is 'cloudformation:DeleteStack'. The other options are not valid IAM actions.

✅ Best Practice

advanced

What is the recommended approach to update a CloudFormation stack with minimal downtime?

You need to update a CloudFormation stack that runs a web application. Which approach minimizes downtime during the update?

A Delete the stack and create a new one with the updated template immediately.

B Manually update resources outside CloudFormation to avoid stack updates.

C Use Change Sets to preview changes and update the stack during low traffic periods.

D Update the stack directly without previewing changes to speed up deployment.

💡 Hint

Think about how to safely apply changes with visibility before execution.

Using Change Sets allows you to preview the impact of changes before applying them, reducing the risk of downtime. Deleting the stack causes downtime, updating without preview risks errors, and manual updates break stack management.

🧠 Conceptual

expert

What is the effect of setting the 'DeletionPolicy' attribute to 'Snapshot' on an Amazon RDS instance in a CloudFormation stack when the stack is deleted?

You have an Amazon RDS instance defined in a CloudFormation stack with the 'DeletionPolicy' attribute set to 'Snapshot'. What happens to the RDS instance when you delete the stack?

A CloudFormation creates a snapshot of the RDS instance before deleting it.

B The RDS instance is deleted immediately without any snapshot.

C The RDS instance is retained and not deleted or snapshotted.

D The stack deletion fails with an error due to the snapshot policy.

💡 Hint

Consider what the 'Snapshot' deletion policy does for stateful resources.

Setting 'DeletionPolicy' to 'Snapshot' causes CloudFormation to create a snapshot of the resource before deleting it, preserving data. The resource is then deleted. 'Retain' would keep the resource, and deletion does not fail due to this policy.