Question

You are authoring a reusable module named 'network' that provisions a VPC and subnets. The parent (root) configuration needs to reference the VPC ID created inside the module so it can pass that value to a separate 'compute' module. Inside the 'network' module, the VPC is defined as 'resource "aws_vpc" "main"'. What must you do so the root configuration can access the VPC ID?

Accepted Answer

Declare an output block in the 'network' module (e.g., output "vpc_id" { value = aws_vpc.main.id }), then reference it as module.network.vpc_id in the root configuration.

Answer

Reference aws_vpc.main.id directly from the root configuration, since all resource attributes are globally accessible once created.

Answer

Add a variable block for vpc_id in the 'network' module so the value is exported to the parent configuration.

Answer

Use a data source in the root configuration to read the VPC, because module resource attributes cannot be passed between modules.