Challenge - Build and Use a Custom Terraform Module

A Terraform module packages a repeatable pattern, inputs, resources, and outputs, into a directory you can call from many configurations. Instead of copying the same EC2 and security-group blocks for every application tier, you define the pattern once and pass in the values that differ: image, size, subnet, a name, and the port to open. Each call gets its own resources, and the root configuration re-exports whatever instance IDs and addresses callers need.

That reusability is the difference between a one-off script and infrastructure you can review, version, and scale. Child modules keep the implementation in one place; the root stays a short list of calls and outputs.

By completing this Intermediate challenge, you will be able to:

• Design a reusable Terraform module with well-chosen inputs, resources, and outputs
• Parameterize one module definition so it can stand up multiple distinct tiers
• Invoke a child module more than once from a root configuration
• Surface child-module results through root-level outputs

Prerequisites

Before attempting this challenge, you should be comfortable with:

• Writing and editing Terraform configuration files (HCL syntax)
• Declaring AWS EC2 instances and security groups in Terraform
• The core Terraform workflow (init, plan, apply)
• Terraform modules, input variables, and outputs