Quickstart: Create an Azure key vault and key using Terraform

Article
08/07/2024

Azure Key Vault is a cloud service that provides a secure store for secrets, such as keys, passwords, and certificate. This article focuses on the process of deploying a Terraform file to create a key vault and a key.

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.

In this article, you learn how to:

Create a random value for the Azure resource group name using random_pet
Create an Azure resource group using azurerm_resource_group
Create a random value using random_string
Create an Azure key vault using azurerm_key_vault
Create an Azure key vault key using azurerm_key_vault_key

Prerequisites

Install and configure Terraform

Implement the Terraform code

Note

The sample code for this article is located in the Azure Terraform GitHub repo. You can view the log file containing the test results from current and previous versions of Terraform.

See more articles and sample code showing how to use Terraform to manage Azure resources

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

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

terraform {
  required_version = ">=1.0"
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~>3.0"
    }
    random = {
      source  = "hashicorp/random"
      version = "~>3.0"
    }
  }
}
provider "azurerm" {
  features {}
}

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

resource "random_pet" "rg_name" {
  prefix = var.resource_group_name_prefix
}

resource "azurerm_resource_group" "rg" {
  name     = random_pet.rg_name.id
  location = var.resource_group_location
}

data "azurerm_client_config" "current" {}

resource "random_string" "azurerm_key_vault_name" {
  length  = 13
  lower   = true
  numeric = false
  special = false
  upper   = false
}

locals {
  current_user_id = coalesce(var.msi_id, data.azurerm_client_config.current.object_id)
}

resource "azurerm_key_vault" "vault" {
  name                       = coalesce(var.vault_name, "vault-${random_string.azurerm_key_vault_name.result}")
  location                   = azurerm_resource_group.rg.location
  resource_group_name        = azurerm_resource_group.rg.name
  tenant_id                  = data.azurerm_client_config.current.tenant_id
  sku_name                   = var.sku_name
  soft_delete_retention_days = 7

  access_policy {
    tenant_id = data.azurerm_client_config.current.tenant_id
    object_id = local.current_user_id

    key_permissions    = var.key_permissions
    secret_permissions = var.secret_permissions
  }
}

resource "random_string" "azurerm_key_vault_key_name" {
  length  = 13
  lower   = true
  numeric = false
  special = false
  upper   = false
}

resource "azurerm_key_vault_key" "key" {
  name = coalesce(var.key_name, "key-${random_string.azurerm_key_vault_key_name.result}")

  key_vault_id = azurerm_key_vault.vault.id
  key_type     = var.key_type
  key_size     = var.key_size
  key_opts     = var.key_ops

  rotation_policy {
    automatic {
      time_before_expiry = "P30D"
    }

    expire_after         = "P90D"
    notify_before_expiry = "P29D"
  }
}

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

variable "resource_group_location" {
  type        = string
  description = "Location for all resources."
  default     = "eastus"
}

variable "resource_group_name_prefix" {
  type        = string
  description = "Prefix of the resource group name that's combined with a random ID so name is unique in your Azure subscription."
  default     = "rg"
}

variable "vault_name" {
  type        = string
  description = "The name of the key vault to be created. The value will be randomly generated if blank."
  default     = ""
}

variable "key_name" {
  type        = string
  description = "The name of the key to be created. The value will be randomly generated if blank."
  default     = ""
}

variable "sku_name" {
  type        = string
  description = "The SKU of the vault to be created."
  default     = "standard"
  validation {
    condition     = contains(["standard", "premium"], var.sku_name)
    error_message = "The sku_name must be one of the following: standard, premium."
  }
}

variable "key_permissions" {
  type        = list(string)
  description = "List of key permissions."
  default     = ["List", "Create", "Delete", "Get", "Purge", "Recover", "Update", "GetRotationPolicy", "SetRotationPolicy"]
}

variable "secret_permissions" {
  type        = list(string)
  description = "List of secret permissions."
  default     = ["Set"]
}

variable "key_type" {
  description = "The JsonWebKeyType of the key to be created."
  default     = "RSA"
  type        = string
  validation {
    condition     = contains(["EC", "EC-HSM", "RSA", "RSA-HSM"], var.key_type)
    error_message = "The key_type must be one of the following: EC, EC-HSM, RSA, RSA-HSM."
  }
}

variable "key_ops" {
  type        = list(string)
  description = "The permitted JSON web key operations of the key to be created."
  default     = ["decrypt", "encrypt", "sign", "unwrapKey", "verify", "wrapKey"]
}

variable "key_size" {
  type        = number
  description = "The size in bits of the key to be created."
  default     = 2048
}

variable "msi_id" {
  type        = string
  description = "The Managed Service Identity ID. If this value isn't null (the default), 'data.azurerm_client_config.current.object_id' will be set to this value."
  default     = null
}

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

output "resource_group_name" {
  value = azurerm_resource_group.rg.name
}

output "azurerm_key_vault_name" {
  value = azurerm_key_vault.vault.name
}

output "azurerm_key_vault_id" {
  value = azurerm_key_vault.vault.id
}

Initialize Terraform

Run terraform init to initialize the Terraform deployment. This command downloads the Azure provider required to manage your Azure resources.

terraform init -upgrade

Key points:

The -upgrade parameter upgrades the necessary provider plugins to the newest version that complies with the configuration's version constraints.

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.

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.

Get the Azure key vault name.

azurerm_key_vault_name=$(terraform output -raw azurerm_key_vault_name)

Run az keyvault key list to display information about the key vault's keys.
```
az keyvault key list --vault-name $azurerm_key_vault_name
```

Get the Azure key vault name.

$azurerm_key_vault_name=$(terraform output -raw azurerm_key_vault_name)

Run Get-AzKeyVault to display information about the new key vault.
```
Get-AzKeyVaultKey -VaultName $azurerm_key_vault_name
```

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

Key Vault security overview

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Quickstart: Create an Azure key vault and key using Terraform

Prerequisites

Implement the Terraform code

Initialize Terraform

Create a Terraform execution plan

Apply a Terraform execution plan

Verify the results

Clean up resources

Troubleshoot Terraform on Azure

Next steps

Feedback

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