18. CloudFormation

Question 1

What are the CloudFormation template components?

Answer 1

1. Resources (MANDATORY)
2. Parameters
3. Mappings
4. Outputs
5. Conditionals
6. Metadata

Question 2

What are CloudFormation parameters?

Answer 2

Parameters are a way to provide inputs to your CloudFormation template. They’re important for when you want to REUSE templates across the company

Question 3

Can you create a dynamic amount of resources using CloudFormation?

Answer 3

No. Everything in the CloudFormation template has to be declared. You can’t perform code generation there

Question 4

How do you reference a parameter in CloudFormation?

Answer 4

Fn::Ref

!Ref in YAML

Question 5

What are CloudFormation mappings?

Answer 5

Mappings are fixed variables within your CloudFormation Template. They’re handy to differentiate between different environments (dev vs prod). All the values are hardcoded within the template

Question 6

How do you reference a mapping in CloudFormation?

Answer 6

Fn::FindInMap

!FindInMap in YAML

Question 7

How do you reference an attribute in CloudFormation?

Answer 7

Fn::GetAtt

Question 8

What is the default CloudFormation Rollback for stack creation failure?

Answer 8

Everything rolls back (gets deleted)

• we can look at the log
• option to disable rollback and troubleshoot what happened

Question 9

What is the default CloudFormation Rollback for stack update failure?

Answer 9

The stack will automatically rollback to the previous known working state
- ability to see in the log what happened and error messages

Question 10

What do you use to create, update, or delete stacks across multiple accounts and regions with a single operation?

Answer 10

CloudFormation StackSets

• administrator account to create StackSets
• when you update a stack set, all associated stack instances are updated throughout all accounts and regions

Question 11

Which section of a CloudFormation template does not allow for conditions?

Answer 11

Parameters

Parameters enable you to input custom values to your CloudFormation template each time you create or update a stack.

Question 12

Exported Output Values in CloudFormation must have unique names:

a. within a single Region
b. across all Regions

Answer 12

Exported Output Values in CloudFormation must have unique names within a single Region

Question 13

When are CF cross stacks helpful?

Answer 13

• when stacks have different life cycles
• when you need to pass export values to many stacks (VPC ID, etc)

Cross stacks use Outputs Export and Fn::ImportValue

Question 14

When are CF nested stacks helpful?

Answer 14

• when components must be reused (ex: reuse how to properly configure an ALB)
• the nested stack is only important to the higher level stack (it’s not shared)