Azure Terraform: Part 6 – Knowledge Review

Reading Time: 3 minutes

Hope you are enjoying learning the magic of Terraform and seeing its endless possibilities in designing and deploying your cloud landscape. In this blog post we will review the concepts we have covered to date.

Azure Providers

In part 2 of this series we covered Terraform Providers, specifically the Azure Provider (azurerm). We also deployed a features block, which is a requirement but can be left empty.

provider "azurerm" {
  features {}
}

Resource Group

In part 3 we covered deploying your first resource Azure Resource Group. A container that would go onto to hold all the cloud resources we will deploy.

resource "azurerm_resource_group" "ftrg001" {
  name     = "FT23-RG-001"
  location = "uksouth"

  tags = {
    environment = "dev"
  }
}

The code bock also introduced our first optional argument, tags. You will notice in most environments tags are forced through policy, deploying resources tagging will be enforced. For further information click the following link.

We also took a moment to cover the main Terraform commands we will be using,

CommandDescription
terraform initInitializes a Terraform working directory, preparing it for configuration and resource management.
terraform validateValidates the syntax and structure of the Terraform configuration files.
terraform plan
Generates an execution plan, showing the proposed changes to infrastructure before applying them.
terraform applyApplies the changes specified in the Terraform configuration, creating or modifying resources.
terraform destroyDestroys all resources created by Terraform, effectively reverting the infrastructure to its initial state.

Azure Networking

In part 4 we covered Azure networking, specifically creating a VNET and Subnet that will be used by future deployed resources.

resource "azurerm_virtual_network" "ftvnet" {
  name                = "ftvnet01"
  address_space       = ["10.10.0.0/16"]
  location            = "uksouth"
  resource_group_name = azurerm_resource_group.ftrg001.name

  tags = {
    environment = "dev"
  }

}

We covered the concept of Terraform being Idempotent. Terraform will only update infrastructure in your environment that has changed based on the code you define. In our example, deploying the VNET and Subnet to the existing resource group did not effect previously deployed resources, they were not deleted or re-created.

You may have also noticed, certain resources defined within the code block, resource_group_name we have not typed out the name of the resource group but referenced its alias and the name attribute of that alias, azurerm_resource_group.ftrg001.name. to break this down,

  • azurerm_resource_group: This is the Terraform resource type for Azure Resource Groups. It’s part of the azurerm provider, which is responsible for managing Azure resources.
  • ftrg001: This is an alias or name given to the specific instance of the azurerm_resource_group resource. When defining resources in Terraform, you provide a name or alias making it easier to refer to that resource in other parts of your configuration.
  • .name: This is accessing the name attribute of the azurerm_resource_group resource. In our example code we named out resource group FT-RG-001

We can also use aliases to refer to these resources, a topic we will cover in future blog posts.

Azure NSG

In part 5 Azure NSG took centre stage as one of the guardians of your Azure Azure Cloud environment. NSG allowed you to defined traffic rules for both inbound and outbound traffic

resource "azurerm_network_security_group" "ftnsg01" {
  name                = "ft-test-nsg01"
  location            = "uksouth"
  resource_group_name = azurerm_resource_group.ftrg001.name

  security_rule = [
    {
      name                                       = "SSH"
      priority                                   = 1001
      direction                                  = "Inbound"
      access                                     = "Allow"
      protocol                                   = "Tcp"
      source_port_range                          = "*"
      destination_port_range                     = "22"

Through out the series we have used a number of Azure CLI commands to validate our and deployments.

AZ CLI Commands

The commands have been consolidated into the following table for your referance,

CommandDescription
az loginAuthenticate to Azure
az account set --subscription <ID>Set the active Azure subscription
az group create --name <name> --location <location>Create an Azure Resource Group
az group delete --name <name> --yesDelete an Azure Resource Group
az group listList all Azure Resource Groups
az vm create --resource-group <rg> --name <vm-name> --image <image>Create an Azure Virtual Machine
az network nsg rule create ...Create a rule in a Network Security Group
az network vnet create ...Create an Azure Virtual Network
az network vnet subnet create ...Create a subnet in an Azure Virtual Network

You may be wondering how Terraform keeps track of all the changes you make to your environment. This is the magic of Terraform State. We will cover Terraform State in our next post in this series. Happy reviewing.

Tags: ,