Day 28: Mastering Terraform Commands Part 1

Adrian Rubico

|

Apr 4, 2025

•

01:01 AM GMT+8

Day 28: Mastering Terraform Commands Part 01

In this blog, we will explore essential Terraform commands that help validate, format, and plan infrastructure before applying it. We will also walk through a hands-on task using Terraform to create an Azure resource group while debugging common errors.

Task: Explore Terraform Commands Part 1

Prerequisites

Before proceeding with the task, ensure you have the following:

bash 
az account set --subscription "YOUR_SUBSCRIPTION_ID"

Update Terraform File

We will update the Terraform File from Day 27 instead of creating a new one. You can modify your existing file or download the prepared template for this demo.

Please modify named main.tf. Copy and paste the following Terraform configuration:

hcl 
terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "4.25.0"
    }
  }
}

provider "azurerm" {
  subscription_id = "YOUR_AZ_SUBSCRIPTION_ID"
  features {}
}

resource "azure_resource_group" "example" {
  name     = "example"
  location = "US East"
}

Now, we will explore Terraform commands with this configuration.

💡 The features {} block is always required by azurerm.

Terraform fmt

Terraform provides the terraform fmt command to format configuration files according to the standard style. Running this command ensures the consistency of your Terraform files.

Example Unformatted Terraform Script:

hcl 
terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "4.25.0"
}
}
}

provider "azurerm" {
   subscription_id = "YOUR_AZ_SUBSCRIPTION_ID"
   features {}
  }
  
resource "azurerm_resource_group" "example" {
  name = "example"
  location="US East"
}

Run the command:

bash 
terraform fmt
Fix Unformatted Terraform Script

Terraform validate

The terraform validate command checks whether your configuration is valid. Let’s run it on our existing Terraform script.

Modify the main.tf file with an incorrect attribute:

hcl 
resource "azurerm_resource_group" "example" {
   name     = "example"
   location = "US East"
   foo      = "boo"
}

Run the command:

bash 
terraform validate
Terraform Validate encounter error, due to the incorrect providing argument.

This error occurs because foo is not a valid attribute for an Azure resource group. You can check the Terraform documentation for the correct Arguments Reference.

Fix the error by replacing foo with valid attribute like tags:

hcl 
resource "azurerm_resource_group" "example" {
   name     = "example"
   location = "US East"
   tags = {
     environment = "dev"
   }
}

Execute terraform validate command to confirm the changes:

Fix the correct argument and run terraform validate.

Terraform plan

The terraform plan command lets us preview the execution plan before applying the changes.

Run the command:

bash 
terraform plan
Execute terraform plan and encounter an error. Because the supported locations are not listed in azurerm.

Now, this happens because "US East" is incorrect. Terraform provides a list of supported locations.

Use the correct location:

hcl 
resource "azurerm_resource_group" "example" {
   name     = "example"
   location = "East US" # OR "eastus"
}

Execute terraform plan command again:

Execute terraform plan is working properly.

Terraform Apply

The terraform apply command is used to create or update infrastructure as defined in Terraform configuration files.

bash 
terraform apply
Execute terraform apply.

Type yes and press Enter. Terraform will create the resource group in Azure.

💡Use -auto-approve flag to automatically approves and applies the changes without prompting the user for confirmation.

Verify the Resource in Azure

After successful execution, verify that the resource group in the Azure Portal:

Azure Resource Group has been created in Azure Portal.

Wrapping Up

In this blog, we explored essential Terraform commands such as terraform fmt, terraform validate, terraform plan, and terraform apply. We also debugged common errors and ensured that Terraform was correctly configured to deploy resources to Azure.

In the next blog, we will continue with Mastering Terraform Commands Part 2, where we will explore terraform variables and other advanced Terraform commands.

TAGS:

#90DaysDevOpsChallenge InfrastructureasCode terraform tfcommands azure

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