Arguments and expressions in Terraform - Mini Project: Build & Apply

Terraform Arguments and Expressions

📖 Scenario: You are setting up a simple cloud infrastructure using Terraform. You want to create a virtual machine with specific settings. To do this, you will use arguments and expressions in Terraform configuration files.

🎯 Goal: Build a Terraform configuration that defines a virtual machine resource with arguments and uses expressions to set values dynamically.

📋 What You'll Learn

Create a variable for the VM name

Define a resource block for a virtual machine

Use expressions to set the VM size based on a condition

Add a tag to the VM using an expression

💡 Why This Matters

🌍 Real World

Terraform is widely used to automate cloud infrastructure setup. Using arguments and expressions lets you create flexible and reusable configurations.

💼 Career

Understanding Terraform arguments and expressions is essential for cloud engineers and DevOps professionals to write efficient infrastructure as code.

1

Create a variable for the VM name

Create a Terraform variable called vm_name with the default value "my-vm".

Terraform

# Create a variable called vm_name with default "my-vm"
# Your code here

Need a hint?

Use the variable block with a default argument.

2

Define a resource block for a virtual machine

Add a resource block called azurerm_linux_virtual_machine named example. Set the name argument to use the variable vm_name.

Terraform

variable "vm_name" {
  type = string
  default = "my-vm"
}

# Add resource block azurerm_linux_virtual_machine named example
# Set name argument to use var.vm_name
# Your code here

Need a hint?

Use resource "azurerm_linux_virtual_machine" "example" {} and set name = var.vm_name.

3

Use expressions to set the VM size based on a condition

Inside the azurerm_linux_virtual_machine.example resource, add an argument size that uses a conditional expression. If var.vm_name is equal to "my-vm", set size to "Standard_B1s", otherwise set it to "Standard_B2s".

Terraform

variable "vm_name" {
  type = string
  default = "my-vm"
}

resource "azurerm_linux_virtual_machine" "example" {
  name = var.vm_name
  # Add size argument with conditional expression
  # Your code here
}

Need a hint?

Use the ternary operator: condition ? true_value : false_value.

4

Add a tag to the VM using an expression

Inside the azurerm_linux_virtual_machine.example resource, add a tags argument. Set the tag Environment to "Production" if var.vm_name contains the substring "prod", otherwise set it to "Development". Use the strcontains() function in the expression.

Terraform

variable "vm_name" {
  type = string
  default = "my-vm"
}

resource "azurerm_linux_virtual_machine" "example" {
  name = var.vm_name
  size = var.vm_name == "my-vm" ? "Standard_B1s" : "Standard_B2s"
  # Add tags argument with Environment tag using strcontains() function
  # Your code here
}

Need a hint?

Use tags = { Environment = strcontains(var.vm_name, "prod") ? "Production" : "Development" }.