Terraform Modules — Challenge

The goal#

Achieve the same outcome as Terraform Modules, from an empty starting point, without the steps.

The configuration from the previous lab works, and now a second environment needs the same shape with different addresses. Copying the directory is the obvious move and the wrong one — two copies drift, and the drift is discovered during an incident.

A module is how the same definition serves both.

What must be true when you are done#

• A modules/network module creates a VPC and subnets from inputs, exposing subnet ids as outputs.
• A modules/compute module places an instance into a subnet it did not create.
• The root module wires them together with no hardcoded ids anywhere.
• Calling the network module twice with different CIDRs produces two independent networks.
• You can explain why the compute module never references aws_vpc directly.

Rules#

• Do not open the guided lab until you are finished, or until the same problem has held you up for 20 minutes.
• Documentation is allowed. In the job it is the first thing you open.
• Verify every criterion with a command whose output you can read.

If you get stuck#

1. What did you expect, exactly?
2. What happened instead — the error text, not a paraphrase?
3. Which layer is that error from?
4. What is the smallest command that proves the layer below is fine?