Configure Azure Compute Gallery with Terraform

Article
10/27/2023

Terraform enables the definition, preview, and deployment of cloud infrastructure. Using Terraform, you create configuration files using HCL syntax. The HCL syntax allows you to specify the cloud provider - such as Azure - and the elements that make up your cloud infrastructure. After you create your configuration files, you create an execution plan that allows you to preview your infrastructure changes before they're deployed. Once you verify the changes, you apply the execution plan to deploy the infrastructure.

This article shows you how to configure Azure Compute Gallery.

In this article, you learn how to:

Use Terraform to configure Azure Compute Gallery (formerly Shared Image Gallery)

1. Configure your environment

Azure subscription: If you don't have an Azure subscription, create a free account before you begin.

Configure Terraform: If you haven't already done so, configure Terraform using one of the following options:

2. Implement the Terraform code

Create a directory in which to test the sample Terraform code and make it the current directory.

Create a file named providers.tf and insert the following code:

terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~>2.0"
    }
    azuread = {
      source = "hashicorp/azuread"
    }
  }
}

provider "azurerm" {
  features {}
}

Create a file named main.tf and insert the following code:

resource "azurerm_resource_group" "sigrg" {
  location = var.deploy_location
  name     = var.rg_shared_name
}

# generate a random string (consisting of four characters)
# https://registry.terraform.io/providers/hashicorp/random/latest/docs/resources/string
resource "random_string" "rando" {
  length  = 4
  upper   = false
  special = false
}


# Creates Shared Image Gallery
# https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/shared_image_gallery
resource "azurerm_shared_image_gallery" "sig" {
  name                = "sig${random_string.random.id}"
  resource_group_name = azurerm_resource_group.sigrg.name
  location            = azurerm_resource_group.sigrg.location
  description         = "Shared images"

  tags = {
    Environment = "Demo"
    Tech        = "Terraform"
  }
}

#Creates image definition
# https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/shared_image
resource "azurerm_shared_image" "example" {
  name                = "avd-image"
  gallery_name        = azurerm_shared_image_gallery.sig.name
  resource_group_name = azurerm_resource_group.sigrg.name
  location            = azurerm_resource_group.sigrg.location
  os_type             = "Windows"

  identifier {
    publisher = "MicrosoftWindowsDesktop"
    offer     = "office-365"
    sku       = "20h2-evd-o365pp"
  }
}

Create a file named variables.tf and insert the following code:

variable "deploy_location" {
  type        = string
  default     = "eastus"
  description = "The Azure Region in which all resources in this example should be created."
}

variable "rg_shared_name" {
  type        = string
  default     = "rg-shared-resources"
  description = "Name of the Resource group in which to deploy shared resources"
}

Create a file named output.tf and insert the following code:

output "location" {
  description = "The Azure region"
  value       = azurerm_resource_group.sigrg.location
}

output "Compute_Gallery" {
  description = "Azure Compute Gallery"
  value       = azurerm_shared_image_gallery.sig.name
}

3. Create a Terraform execution plan

Run terraform plan to create an execution plan.

terraform plan -out main.tfplan

Key points:

The terraform plan command creates an execution plan, but doesn't execute it. Instead, it determines what actions are necessary to create the configuration specified in your configuration files. This pattern allows you to verify whether the execution plan matches your expectations before making any changes to actual resources.
The optional -out parameter allows you to specify an output file for the plan. Using the -out parameter ensures that the plan you reviewed is exactly what is applied.

4. Apply a Terraform execution plan

Run terraform apply to apply the execution plan to your cloud infrastructure.

terraform apply main.tfplan

Key points:

The example terraform apply command assumes you previously ran terraform plan -out main.tfplan.
If you specified a different filename for the -out parameter, use that same filename in the call to terraform apply.
If you didn't use the -out parameter, call terraform apply without any parameters.

5. Clean up resources

When you no longer need the resources created via Terraform, do the following steps:

Run terraform plan and specify the destroy flag.
```
terraform plan -destroy -out main.destroy.tfplan
```
Key points:
- The terraform plan command creates an execution plan, but doesn't execute it. Instead, it determines what actions are necessary to create the configuration specified in your configuration files. This pattern allows you to verify whether the execution plan matches your expectations before making any changes to actual resources.
- The optional -out parameter allows you to specify an output file for the plan. Using the -out parameter ensures that the plan you reviewed is exactly what is applied.
Run terraform apply to apply the execution plan.
```
terraform apply main.destroy.tfplan
```

Troubleshoot Terraform on Azure

Troubleshoot common problems when using Terraform on Azure

Next steps

Learn more about using Terraform in Azure