CloudFormation and CDK

Question 1

What is AWS CloudFormation?

Answer 1

A declarative service to outline and manage AWS infrastructure as code.

Question 2

What are the benefits of CloudFormation?

Answer 2

Infrastructure as code, version control, cost estimation, productivity, reusable templates.

Question 3

How does CloudFormation work?

Answer 3

Templates define resources, uploaded to S3, and referenced by CloudFormation to create/update stacks.

Question 4

What happens when a stack is deleted?

Answer 4

All resources created by the stack are deleted.

Question 5

What are CloudFormation building blocks?

Answer 5

Resources (mandatory), Parameters, Mappings, Outputs, Conditionals, References, Functions.

Question 6

Which languages are used for CloudFormation templates?

Answer 6

YAML and JSON; YAML is preferred.

Question 7

What are CloudFormation resources?

Answer 7

Core components of a template that define AWS infrastructure.

Question 8

Can CloudFormation create dynamic number of resources?

Answer 8

Yes, using Macros and Transforms.

Question 9

What are CloudFormation Parameters?

Answer 9

Inputs to templates for reuse and dynamic configuration.

Question 10

When should you use Parameters?

Answer 10

When values are user-specific or likely to change.

Question 11

What are CloudFormation Mappings?

Answer 11

Fixed variables to differentiate values like region or environment.

Question 12

How to access Mapping values?

Answer 12

Use Fn::FindInMap.

Question 13

When to use Mappings vs Parameters?

Answer 13

Mappings for predictable values, Parameters for dynamic inputs.

Question 14

What are CloudFormation Outputs?

Answer 14

Named values you can declare in your template to return information about the resources that were created. Share values with other stacks (cross-stack references).

Question 15

How to use cross-stack references?

Answer 15

Use Fn::ImportValue in the referencing stack.

Question 16

What are CloudFormation Conditions?

Answer 16

Logic to create resources based on parameter values or environment.

Question 17

How to use a Condition in a resource?

Answer 17

Attach a Condition with logical functions like Fn::If.

Question 18

What is Fn::Ref used for?

Answer 18

Reference parameters and resources.

Question 19

What does Fn::GetAtt do?

Answer 19

Get attributes from a resource (e.g., AZ from an EC2 instance).

Question 20

What does Fn::Base64 do?

Answer 20

Encodes a string to Base64, e.g., for EC2 UserData.

Question 21

What happens when stack creation fails?

Answer 21

Rolls back all created resources unless rollback is disabled.

Question 22

What is a CloudFormation Service Role?

Answer 22

IAM role that AWS CloudFormation assumes on your behalf to create, update, or delete stack resources.

Question 23

What are CAPABILITY_NAMED_IAM and CAPABILITY_IAM?

Answer 23

Explicit acknowledgments you must provide when your CloudFormation template creates or modifies IAM resources

Question 24

What is CAPABILITY_AUTO_EXPAND?

Answer 24

Used when templates use Macros or Nested Stacks.

Question 25

What is DeletionPolicy in CloudFormation?

Answer 25

Controls what happens when a resource is deleted.

Question 26

What does DeletionPolicy Retain do?

Answer 26

Keeps the resource after stack deletion.

Question 27

What does DeletionPolicy Snapshot do?

Answer 27

Creates a snapshot before deleting a resource.

Question 28

What is a Stack Policy?

Answer 28

Defines what resources can be updated during a stack update.

Question 29

How to prevent accidental stack deletion?

Answer 29

Enable TerminationProtection.

Question 30

What are Custom Resources in CloudFormation?

Answer 30

Define custom provisioning logic using Lambda or SNS.

Question 31

What is a use case for Custom Resources?

Answer 31

Empty an S3 bucket before deletion.

Question 32

What are CloudFormation StackSets?

Answer 32

Manage stacks across multiple accounts and regions from one template.

Question 33

What is AWS CDK?

Answer 33

A framework to define cloud infrastructure using programming languages like JavaScript, TypeScript, Python, Java, and .NET.

Question 34

What are CDK constructs?

Answer 34

Components that encapsulate everything CDK needs to create the final CloudFormation stack.

Question 35

What is the purpose of CDK synth?

Answer 35

It synthesizes and prints the CloudFormation template from your CDK code.

Question 36

What is CDK bootstrap?

Answer 36

It deploys the CDK Toolkit stack that includes necessary resources like an S3 bucket and IAM roles.

Question 37

What are CDK L1 constructs?

Answer 37

Low-level constructs mapped directly to CloudFormation resources, names start with 'Cfn'.

Question 38

What are CDK L2 constructs?

Answer 38

Higher-level constructs with convenient defaults and intent-based APIs.

Question 39

What are CDK L3 constructs?

Answer 39

High-level patterns that include multiple related AWS resources for common architectures.

Question 40

What does 'cdk deploy' do?

Answer 40

Deploys the stack(s) to AWS.

Question 41

What does 'cdk diff' do?

Answer 41

Compares local CDK stack with the deployed stack and shows the differences.

Question 42

What is the use of 'cdk destroy'?

Answer 42

Destroys the deployed stack(s) in AWS.

Question 43

What is CDK Toolkit?

Answer 43

A CloudFormation stack created by CDK bootstrap containing an S3 bucket and IAM roles.

Question 44

What happens if CDK is not bootstrapped?

Answer 44

You get an error about invalid principal in the policy.

Question 45

How can CDK be tested?

Answer 45

Using CDK Assertions with test frameworks like Jest or Pytest.

Question 46

What are fine-grained assertions in CDK testing?

Answer 46

Tests that check specific aspects of a resource in the CloudFormation template.

Question 47

What are snapshot tests in CDK?

Answer 47

Tests that compare the synthesized template to a stored baseline template.

Question 48

How to initialize a CDK app?

Answer 48

Use the command 'cdk init app'.

Question 49

What command installs the CDK CLI?

Answer 49

npm install -g aws-cdk-lib

Question 50

What command deploys resources using CDK?

Answer 50

cdk deploy

Question 51

What command destroys a CDK stack?

Answer 51

cdk destroy

Question 52

What is the Construct Hub in CDK?

Answer 52

A collection of additional constructs provided by AWS, 3rd parties, and the open-source community.