Build Infrastructure - Terraform Azure Example

In this tutorial, you will create a Terraform configuration to deploy an Azure resource group. This resource group is the foundation for the infrastructure you will build in the subsequent tutorials.

Prerequisites

• An Azure subscription. If you do not have an Azure account, create one now. This tutorial can be completed using only the services included in an Azure free account.

• Terraform 0.14.9 or later

• The Azure CLI Tool installed

Install the Azure CLI tool

You will use the Azure CLI tool to authenticate with Azure.

$ Invoke-WebRequest -Uri https://aka.ms/installazurecliwindows -OutFile .\AzureCLI.msi; Start-Process msiexec.exe -Wait -ArgumentList '/I AzureCLI.msi /quiet'; rm .\AzureCLI.msi

$ brew update && brew install azure-cli

Authenticate using the Azure CLI

Terraform must authenticate to Azure to create infrastructure.

In your terminal, use the Azure CLI tool to setup your account permissions locally.

$ az login

Your browser will open and prompt you to enter your Azure login credentials. After successful authentication, your terminal will display your subscription information.

You have logged in. Now let us find all the subscriptions to which you have access...

[
  {
    "cloudName": "AzureCloud",
    "homeTenantId": "0envbwi39-home-Tenant-Id",
    "id": "35akss-subscription-id",
    "isDefault": true,
    "managedByTenants": [],
    "name": "Subscription-Name",
    "state": "Enabled",
    "tenantId": "0envbwi39-TenantId",
    "user": {
      "name": "your-username@domain.com",
      "type": "user"
    }
  }
]

Find the id column for the subscription account you want to use.

Once you have chosen the account subscription ID, set the account with the Azure CLI.

$ az account set --subscription "35akss-subscription-id"

Create a Service Principal

Next, create a Service Principal. A Service Principal is an application within Azure Active Directory with the authentication tokens Terraform needs to perform actions on your behalf. Update the <SUBSCRIPTION_ID> with the subscription ID you specified in the previous step.

$ az ad sp create-for-rbac --role="Contributor" --scopes="/subscriptions/<SUBSCRIPTION_ID>"

Creating 'Contributor' role assignment under scope '/subscriptions/35akss-subscription-id'
The output includes credentials that you must protect. Be sure that you do not include these credentials in your code or check the credentials into your source control. For more information, see https://aka.ms/azadsp-cli
{
  "appId": "xxxxxx-xxx-xxxx-xxxx-xxxxxxxxxx",
  "displayName": "azure-cli-2022-xxxx",
  "password": "xxxxxx~xxxxxx~xxxxx",
  "tenant": "xxxxx-xxxx-xxxxx-xxxx-xxxxx"
}

Set your environment variables

HashiCorp recommends setting these values as environment variables rather than saving them in your Terraform configuration.

$ $Env:ARM_CLIENT_ID = "<APPID_VALUE>"
$ $Env:ARM_CLIENT_SECRET = "<PASSWORD_VALUE>"
$ $Env:ARM_SUBSCRIPTION_ID = "<SUBSCRIPTION_ID>"
$ $Env:ARM_TENANT_ID = "<TENANT_VALUE>"

$ export ARM_CLIENT_ID="<APPID_VALUE>"
$ export ARM_CLIENT_SECRET="<PASSWORD_VALUE>"
$ export ARM_SUBSCRIPTION_ID="<SUBSCRIPTION_ID>"
$ export ARM_TENANT_ID="<TENANT_VALUE>"

For more information on Service Principal authentication, visit the Azure provider documentation.

Write configuration

$ New-Item -Path "c:\" -Name "learn-terraform-azure" -ItemType "directory"

$ mkdir learn-terraform-azure

$ cd learn-terraform-azure

Create a new file called main.tf and paste the configuration below.

# Configure the Azure provider
terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~> 3.0.2"
    }
  }

  required_version = ">= 1.1.0"
}

provider "azurerm" {
  features {}
}

resource "azurerm_resource_group" "rg" {
  name     = "myTFResourceGroup"
  location = "westus2"
}

This is a complete configuration that Terraform can apply. In the following sections you will review each block of the configuration in more detail.

Terraform Block

The terraform {} block contains Terraform settings, including the required providers Terraform will use to provision your infrastructure. For each provider, the source attribute defines an optional hostname, a namespace, and the provider type. Terraform installs providers from the Terraform Registry by default. In this example configuration, the azurerm provider's source is defined as hashicorp/azurerm, which is shorthand for registry.terraform.io/hashicorp/azurerm.

You can also define a version constraint for each provider in the required_providers block. The version attribute is optional, but we recommend using it to enforce the provider version. Without it, Terraform will always use the latest version of the provider, which may introduce breaking changes.

To learn more, reference the provider source documentation.

Providers

The provider block configures the specified provider, in this case azurerm. A provider is a plugin that Terraform uses to create and manage your resources. You can define multiple provider blocks in a Terraform configuration to manage resources from different providers.

Resource

Use resource blocks to define components of your infrastructure. A resource might be a physical component such as a server, or it can be a logical resource such as a Heroku application.

Resource blocks have two strings before the block: the resource type and the resource name. In this example, the resource type is azurerm_resource_group and the name is rg. The prefix of the type maps to the name of the provider. In the example configuration, Terraform manages the azurerm_resource_group resource with the azurerm provider. Together, the resource type and resource name form a unique ID for the resource. For example, the ID for your network is azurerm_resource_group.rg.

Resource blocks contain arguments which you use to configure the resource. The Azure provider documentation documents supported resources and their configuration options, including azurerm_resource_group and its supported arguments.

Initialize your Terraform configuration

Initialize your learn-terraform-azure directory in your terminal. The terraform commands will work with any operating system. Your output should look similar to the one below.

$ terraform init
Initializing the backend...

Initializing provider plugins...
- Finding hashicorp/azurerm versions matching "~> 3.0.2"...
- Installing hashicorp/azurerm v3.0.2...
- Installed hashicorp/azurerm v3.0.2 (signed by HashiCorp)

Terraform has been successfully initialized!

You may now begin working with Terraform. Try running "terraform plan" to see
any changes that are required for your infrastructure. All Terraform commands
should now work.

If you ever set or change modules or backend configuration for Terraform,
rerun this command to reinitialize your working directory. If you forget, other
commands will detect it and remind you to do so if necessary.

Format and validate the configuration

We recommend using consistent formatting in all of your configuration files. The terraform fmt command automatically updates configurations in the current directory for readability and consistency.

Format your configuration. Terraform will print out the names of the files it modified, if any. In this case, your configuration file was already formatted correctly, so Terraform won't return any file names.

$ terraform fmt

You can also make sure your configuration is syntactically valid and internally consistent by using the terraform validate command.

Validate your configuration. The example configuration provided above is valid, so Terraform will return a success message.

$ terraform validate
Success! The configuration is valid.

Apply your Terraform Configuration

Run the terraform apply command to apply your configuration.

This output shows the execution plan and will prompt you for approval before proceeding. If anything in the plan seems incorrect or dangerous, it is safe to abort here with no changes made to your infrastructure. Type yes at the confirmation prompt to proceed.

$ terraform apply
An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  # azurerm_resource_group.rg will be created
  + resource "azurerm_resource_group" "rg" {
      + id       = (known after apply)
      + location = "westus2"
      + name     = "myTFResourceGroup"
    }

Plan: 1 to add, 0 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes
azurerm_resource_group.rg: Creating...
azurerm_resource_group.rg: Creation complete after 1s [id=/subscriptions/c9ed8610-47a3-4107-a2b2-a322114dfb29/resourceGroups/myTFResourceGroup]

Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

Navigate to the Azure portal in your web browser to validate the resource group.

Inspect your state

When you apply your configuration, Terraform writes data into a file called terraform.tfstate. This file contains the IDs and properties of the resources Terraform created so that it can manage or destroy those resources going forward. Your state file contains all of the data in your configuration and could also contain sensitive values in plaintext, so do not share it or check it in to source control.

For teams or larger projects, consider storing your state remotely. Remote stage storage enables collaboration using Terraform but is beyond the scope of this tutorial.

Inspect the current state using terraform show.

$ terraform show
# azurerm_resource_group.rg:
resource "azurerm_resource_group" "rg" {
    id       = "/subscriptions/c9ed8610-47a3-4107-a2b2-a322114dfb29/resourceGroups/myTFResourceGroup"
    location = "westus2"
    name     = "myTFResourceGroup"
}

When Terraform created this resource group, it also gathered the resource's properties and meta-data. These values can be referenced to configure other resources or outputs, which you will encounter in later tutorials.

To review the information in your state file, use the state command. If you have a long state file, you can see a list of the resources you created with Terraform by using the list subcommand.

$ terraform state list
azurerm_resource_group.rg

If you run terraform state, you will see a full list of available commands to view and manipulate the configuration's state.

$ terraform state
Usage: terraform state <subcommand> [options] [args]

  This command has subcommands for advanced state management.

  These subcommands can be used to slice and dice the Terraform state.
  This is sometimes necessary in advanced cases. For your safety, all
  state management commands that modify the state create a timestamped
  backup of the state prior to making modifications.

  The structure and output of the commands is specifically tailored to work
  well with the common Unix utilities such as grep, awk, etc. We recommend
  using those tools to perform more advanced state tasks.

Subcommands:
    list                List resources in the state
    mv                  Move an item in the state
    pull                Pull current state and output to stdout
    push                Update remote state from a local state file
    replace-provider    Replace provider in the state
    rm                  Remove instances from the state
    show                Show a resource in the state

Next Steps

For more detail on the concepts used in this tutorial:

• Read about the Terraform configuration language in the Terraform documentation.
• Learn more about Terraform providers.
• Review usage examples of the Terraform Azure provider from Terraform provider engineers