Module composition patterns in Terraform - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Terraform module?

A Terraform module is a container for multiple resources that are used together. It helps organize and reuse infrastructure code like building blocks.

beginner

What does 'module composition' mean in Terraform?

Module composition means combining smaller modules inside bigger modules to build complex infrastructure in a simple, reusable way.

intermediate

Name two common patterns for composing Terraform modules.

1. Nested modules: calling one module inside another. 2. Wrapper modules: modules that group other modules to provide a simpler interface.

intermediate

Why use wrapper modules in Terraform?

Wrapper modules simplify complex setups by grouping multiple modules and exposing only needed inputs and outputs, making it easier to use.

beginner

How do you pass variables between composed Terraform modules?

You pass variables by defining inputs in the child module and providing values from the parent module when calling it.

What is the main benefit of using Terraform modules?

A Avoid using variables

B Increase cloud costs

C Make code harder to read

D Reuse and organize infrastructure code

Modules help reuse and organize infrastructure code, making it easier to manage.

Which pattern involves calling one module inside another in Terraform?

A Nested module

B Singleton module

C Wrapper module

D Flat module

Nested modules are modules called inside other modules to build complex infrastructure.

What is a wrapper module used for?

A To delete resources automatically

B To increase deployment time

C To group multiple modules and simplify usage

D To avoid using outputs

Wrapper modules group other modules and provide a simpler interface.

How do you provide input values to a child module in Terraform?

A By defining variables in the child and passing values from the parent

B By hardcoding values inside the child module

C By using environment variables only

D By copying code manually

Inputs are defined as variables in the child module and values are passed from the parent module.

Which of these is NOT a benefit of module composition?

A Simplified infrastructure management

B Increased code duplication

C Improved code reuse

D Easier collaboration

Module composition reduces code duplication, not increases it.

Explain how nested modules work in Terraform and why they are useful.

Think about how small building blocks combine to make bigger structures.

Describe the purpose of wrapper modules and how they improve Terraform code usability.

Imagine a remote control that controls many devices with fewer buttons.