Variables and outputs in GCP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable in a Terraform configuration.

GCP

variable "project_id" {
  type = [1]
}

Drag options to blanks, or click blank then click option'

Ainteger

Bstring

Cbool

Dlist

Attempts:

3 left

💡 Hint

Common Mistakes

Using integer or bool types for text values.

Leaving the type undefined.

The type of a variable defines what kind of value it holds. For project IDs, string is the correct type.

2fill in blank

medium

Complete the code to output the project ID variable value.

GCP

output "project_id_output" {
  value = [1]
}

Drag options to blanks, or click blank then click option'

Aproject_id

Bvar.project_name

Coutput.project_id

Dvar.project_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using the output name instead of the variable name.

Omitting the var. prefix.

To output a variable's value, use var.variable_name. Here, var.project_id accesses the project ID variable.

3fill in blank

hard

Fix the error in the output block to correctly reference the variable.

GCP

output "region_output" {
  value = [1]
}

Drag options to blanks, or click blank then click option'

Avar.region

Bvar.region_name

Coutput.region

Dregion

Attempts:

3 left

💡 Hint

Common Mistakes

Referencing variables without the var. prefix.

Using incorrect variable names.

The correct way to reference a variable in Terraform output is with var.variable_name. Here, var.region is correct.

4fill in blank

hard

Fill both blanks to declare a variable with a default value and output it.

GCP

variable "region" {
  type    = [1]
  default = [2]
}

output "region_output" {
  value = var.region
}

Drag options to blanks, or click blank then click option'

Astring

B"us-central1"

Cus-central1

Dinteger

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the default string value.

Using wrong type for the variable.

The variable type should be string. The default value must be a quoted string like "us-central1" to be valid.

5fill in blank

hard

Fill all three blanks to declare a variable, assign a default, and output its uppercase value.

GCP

variable "env" {
  type    = [1]
  default = [2]
}

output "env_upper" {
  value = upper([3])
}

Drag options to blanks, or click blank then click option'

Astring

B"prod"

Cvar.env

Dprod

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the default string.

Using the variable name without var. prefix.

Using unquoted strings in output.

The variable type is string. The default value must be a quoted string "prod". To output the uppercase value, use upper(var.env).

Practice

1. What is the main purpose of variables in a Google Cloud deployment configuration?

easy

A. To monitor resource usage in real-time

B. To display the final results after deployment

C. To delete resources automatically

D. To store values that can be reused throughout the configuration

Solution

1. Step 1: Understand the role of variables

   Variables hold values like names or sizes that you want to reuse in your cloud setup.

2. Step 2: Differentiate variables from outputs

   Outputs show results after deployment, but variables store reusable data before deployment.

3. Final Answer:

   To store values that can be reused throughout the configuration -> Option D

4. Quick Check:

   Variables store reusable values [OK]

Hint: Variables hold reusable data; outputs show results after deployment [OK]

Common Mistakes:

• Confusing variables with outputs
• Thinking variables delete resources
• Assuming variables monitor usage

2. Which of the following is the correct syntax to declare a variable named region with default value us-central1 in a Terraform configuration for GCP?

easy

A. var region = "us-central1"

B. variable "region" { default = "us-central1" }

C. set variable region = "us-central1"

D. region := "us-central1"

Solution

1. Step 1: Recall Terraform variable syntax

   Terraform uses the keyword 'variable' followed by the name in quotes and a block with 'default' value.

2. Step 2: Compare options

   variable "region" { default = "us-central1" } matches Terraform syntax exactly; others use invalid or different language syntax.

3. Final Answer:

   variable "region" { default = "us-central1" } -> Option B

4. Quick Check:

   Terraform variable syntax uses 'variable' block [OK]

Hint: Terraform variables use 'variable' block with default inside braces [OK]

Common Mistakes:

• Using assignment syntax from other languages
• Missing quotes around variable name
• Using := which is not Terraform syntax

3. Given this Terraform output block:

output "instance_ip" {
  value = google_compute_instance.vm_instance.network_interface[0].access_config[0].nat_ip
}

What will terraform output instance_ip show after deployment?

medium

A. The public IP address of the VM instance

B. The internal IP address of the VM instance

C. The VM instance name

D. An error because output syntax is wrong

Solution

1. Step 1: Understand the output value path

   The path accesses the VM's network interface, then the first access config's NAT IP, which is the public IP.

2. Step 2: Confirm output command result

   Running 'terraform output instance_ip' returns the value of that output, which is the public IP address.

3. Final Answer:

   The public IP address of the VM instance -> Option A

4. Quick Check:

   Output shows public IP from access_config NAT IP [OK]

Hint: Access NAT IP in output shows public IP address [OK]

Common Mistakes:

• Confusing NAT IP with internal IP
• Assuming output shows instance name
• Thinking output block syntax is invalid

4. You wrote this Terraform variable block:

variable "zone" {
  default = us-central1-a
}

Why does Terraform fail to apply this configuration?

medium

A. The default value is missing quotes around the string

B. Variable name cannot be 'zone'

C. Default values are not allowed in variables

D. The block must use 'var' instead of 'variable'

Solution

1. Step 1: Check the default value syntax

   Terraform requires string values to be in quotes. Here, us-central1-a is unquoted.

2. Step 2: Understand Terraform variable rules

   Variable names like 'zone' are valid, default values are allowed, and 'variable' keyword is correct.

3. Final Answer:

   The default value is missing quotes around the string -> Option A

4. Quick Check:

   Strings need quotes in Terraform variables [OK]

Hint: Always quote string default values in Terraform variables [OK]

Common Mistakes:

• Forgetting quotes around string values
• Thinking variable names are restricted
• Using 'var' instead of 'variable' keyword

5. You want to create a Terraform output that shows the URL of a deployed Cloud Storage bucket using a variable bucket_name. Which output block correctly uses the variable to build the URL?

hard

A. output "bucket_url" { value = "https://storage.googleapis.com/var.bucket_name" }

B. output "bucket_url" { value = https://storage.googleapis.com/${bucket_name} }

C. output "bucket_url" { value = "https://storage.googleapis.com/${var.bucket_name}" }

D. output "bucket_url" { value = "https://storage.googleapis.com/bucket_name" }

Solution

1. Step 1: Understand variable interpolation syntax

   Terraform uses ${var.variable_name} inside strings to insert variable values.

2. Step 2: Check each option for correct syntax

   output "bucket_url" { value = "https://storage.googleapis.com/${var.bucket_name}" } correctly uses "${var.bucket_name}" inside quotes. Others either miss quotes or use wrong syntax.

3. Final Answer:

   output "bucket_url" { value = "https://storage.googleapis.com/${var.bucket_name}" } -> Option C

4. Quick Check:

   Use ${var.name} for variable interpolation in outputs [OK]

Hint: Use ${var.name} inside quotes for variable interpolation [OK]

Common Mistakes:

• Missing quotes around the URL string
• Not using 'var.' prefix for variables
• Using variable name without interpolation syntax