Variables and outputs in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Terraform variable default values

You have a Terraform variable defined as:

variable "region" {
  type    = string
  default = "us-central1"
}

What will be the value of var.region if you do not provide any value during terraform apply?

A It will be "us-central1".

B Terraform will throw an error for missing variable value.

C It will be null.

D It will be an empty string.

💡 Hint

Check the default attribute in the variable block.

If a variable has a default value, Terraform uses it when no other value is provided.

❓ Configuration

intermediate

Outputting a resource attribute in Terraform

Given this Terraform resource:

resource "google_compute_instance" "vm" {
  name         = "my-vm"
  machine_type = "e2-medium"
  zone         = "us-central1-a"
  boot_disk {
    initialize_params {
      image = "debian-cloud/debian-11"
    }
  }
  network_interface {
    network = "default"
  }
}

Which output block correctly exports the VM's self_link attribute?

A output "vm_self_link" { value = google_compute_instance.vm.zone }

B output "vm_self_link" { value = google_compute_instance.vm.self_link }

C output "vm_self_link" { value = google_compute_instance.vm.network }

D output "vm_self_link" { value = google_compute_instance.vm.name }

💡 Hint

Look for the attribute that uniquely identifies the resource URL.

The self_link attribute provides the full URL of the resource, which is often used as an output.

❓ Architecture

advanced

Passing variables between Terraform modules

You have a root Terraform module that calls a child module. The child module expects a variable named project_id. Which root module code snippet correctly passes the root variable var.project to the child module?

A module "child" { source = "./child" project_id = var.project_id }

B module "child" { source = "./child" project = var.project_id }

C module "child" { source = "./child" project_id = var.project }

D module "child" { source = "./child" project = var.project }

💡 Hint

Match the variable names expected by the child module with the root variables.

The child module expects a variable named project_id, so the root module must pass var.project to project_id.

❓ security

advanced

Avoiding sensitive data exposure in Terraform outputs

You have a Terraform variable marked as sensitive:

variable "db_password" {
  type      = string
  sensitive = true
}

Which output block will cause Terraform to hide the password value when you run terraform apply?

A output "db_password" { value = var.db_password }

B output "db_password" { value = var.db_password redact = true }

C output "db_password" { value = var.db_password hidden = true }

D output "db_password" { value = var.db_password sensitive = true }

💡 Hint

Check the Terraform output block attribute to mark outputs as sensitive.

Setting sensitive = true in the output block hides the value in CLI output.

❓ service_behavior

expert

Effect of missing output declaration in Terraform module

You have a Terraform child module that creates a Google Cloud Storage bucket. The child module does NOT declare any outputs.

When you call this module from the root module and run terraform apply, what will be the state of the bucket's URL in the root module?

A The bucket URL will NOT be available in the root module because no output is declared.

B The bucket URL will be available as module.child.bucket_url automatically.

C Terraform will throw an error during apply due to missing output.

D The bucket URL will be stored in a default output named bucket_url.

💡 Hint

Outputs must be explicitly declared to be accessible outside a module.

Terraform modules only expose outputs that are explicitly declared. Without an output, the root module cannot access the bucket URL.