Creating stacks in AWS - Practice Exercises

Challenge - 5 Problems

❓ service_behavior

intermediate

Stack Creation Behavior with Missing Parameters

You create an AWS CloudFormation stack using a template that requires a parameter named InstanceType. You run the create-stack command without specifying this parameter. What will happen?

A The stack creation fails immediately with a validation error about the missing parameter.

B The stack creation waits indefinitely for the parameter to be provided.

C The stack creation succeeds but the resource using <code>InstanceType</code> is skipped.

D The stack is created with a default value for <code>InstanceType</code> if defined in the template.

💡 Hint

Think about how CloudFormation handles parameters with and without default values.

If a parameter has a default value defined in the template, CloudFormation uses it when the parameter is not provided during stack creation. Otherwise, it raises a validation error.

❓ Architecture

intermediate

Stack Dependency Management

You have two CloudFormation stacks: NetworkStack creates a VPC, and AppStack creates EC2 instances inside that VPC. How should you ensure AppStack only creates resources after NetworkStack is complete?

A Create <code>AppStack</code> first, then create <code>NetworkStack</code> after.

B Manually wait for <code>NetworkStack</code> to complete before creating <code>AppStack</code>.

C Use the <code>DependsOn</code> attribute in <code>AppStack</code> to depend on <code>NetworkStack</code>.

D Use stack outputs and import values from <code>NetworkStack</code> in <code>AppStack</code>.

💡 Hint

Consider how CloudFormation stacks share information and dependencies.

CloudFormation does not support DependsOn between stacks. Instead, you export outputs from one stack and import them in another to create implicit dependencies.

❓ security

advanced

IAM Role Permissions for Stack Creation

You want to automate CloudFormation stack creation using an IAM role. Which permission is required for the role to successfully create stacks?

A cloudformation:CreateStack

B ec2:CreateInstance

C iam:PassRole

D s3:PutObject

💡 Hint

Focus on the permissions related to CloudFormation stack operations.

The cloudformation:CreateStack permission allows creating stacks. Other permissions may be needed depending on resources, but this is essential.

✅ Best Practice

advanced

Stack Update Strategy to Avoid Downtime

You need to update a CloudFormation stack that runs a web application. What is the best practice to avoid downtime during the update?

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

B Use stack update with <code>UpdatePolicy</code> to perform rolling updates.

C Manually stop the application, update the stack, then start the application.

D Update the stack and immediately rollback if errors occur.

💡 Hint

Look for CloudFormation features that help update resources without downtime.

The UpdatePolicy attribute allows rolling updates for resources like Auto Scaling groups, minimizing downtime.

🧠 Conceptual

expert

Stack Drift Detection Outcome

You run drift detection on a CloudFormation stack and it reports drift on one resource. What does this mean?

A The stack has pending updates waiting to be applied.

B The resource was deleted outside CloudFormation.

C The resource's actual configuration differs from the stack template.

D The stack is in rollback state due to an error.

💡 Hint

Think about what drift detection compares.

Drift detection compares the actual resource configuration with the expected configuration defined in the stack template. Drift means they differ.