Quickstart: Use Terraform to create an Azure IoT Device Provisioning Service

Article
12/07/2022

In this quickstart, you will learn how to deploy an Azure IoT Hub Device Provisioning Service (DPS) resource with a hashed allocation policy using Terraform.

This quickstart was tested with the following Terraform and Terraform provider versions:

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 Storage Account & Storage Container
Create an Event Hubs, Namespace, & Authorization Rule
Create an IoT Hub
Link IoT Hub to Storage Account endpoint & Event Hubs endpoint
Create an IoT Hub Shared Access Policy
Create a DPS Resource
Link DPS & IoT Hub

Prerequisites

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

Install and configure Terraform

Implement the Terraform code

Note

The example code in this article is located in the Azure Terraform GitHub repo. 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" {
  location = var.resource_group_location
  name     = random_pet.rg_name.id
}

# Create storage account & container
resource "random_string" "sa_name" {
  length  = 12
  special = false
  upper   = false
}

resource "azurerm_storage_account" "sa" {
  name                     = random_string.sa_name.id
  resource_group_name      = azurerm_resource_group.rg.name
  location                 = azurerm_resource_group.rg.location
  account_tier             = "Standard"
  account_replication_type = "LRS"
}

resource "azurerm_storage_container" "my_terraform_container" {
  name                  = "mycontainer"
  storage_account_name  = azurerm_storage_account.sa.name
  container_access_type = "private"
}


# Create an Event Hub & Authorization Rule
resource "random_pet" "eventhub_namespace_name" {
  prefix = var.eventhub_namespace_name_prefix
}

resource "azurerm_eventhub_namespace" "namespace" {
  name                = random_pet.eventhub_namespace_name.id
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location
  sku                 = "Basic"
}

resource "azurerm_eventhub" "my_terraform_eventhub" {
  name                = "myEventHub"
  resource_group_name = azurerm_resource_group.rg.name
  namespace_name      = azurerm_eventhub_namespace.namespace.name
  partition_count     = 2
  message_retention   = 1
}

resource "azurerm_eventhub_authorization_rule" "my_terraform_authorization_rule" {
  resource_group_name = azurerm_resource_group.rg.name
  namespace_name      = azurerm_eventhub_namespace.namespace.name
  eventhub_name       = azurerm_eventhub.my_terraform_eventhub.name
  name                = "acctest"
  send                = true
}


# Create an IoT Hub
resource "random_pet" "iothub_name" {
  prefix = var.iothub_name_prefix
  length = 1
}

resource "azurerm_iothub" "iothub" {
  name                = random_pet.iothub_name.id
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location

  sku {
    name     = "S1"
    capacity = 1
  }

  endpoint {
    type                       = "AzureIotHub.StorageContainer"
    connection_string          = azurerm_storage_account.sa.primary_blob_connection_string
    name                       = "export"
    batch_frequency_in_seconds = 60
    max_chunk_size_in_bytes    = 10485760
    container_name             = azurerm_storage_container.my_terraform_container.name
    encoding                   = "Avro"
    file_name_format           = "{iothub}/{partition}_{YYYY}_{MM}_{DD}_{HH}_{mm}"
  }

  endpoint {
    type              = "AzureIotHub.EventHub"
    connection_string = azurerm_eventhub_authorization_rule.my_terraform_authorization_rule.primary_connection_string
    name              = "export2"
  }

  route {
    name           = "export"
    source         = "DeviceMessages"
    condition      = "true"
    endpoint_names = ["export"]
    enabled        = true
  }

  route {
    name           = "export2"
    source         = "DeviceMessages"
    condition      = "true"
    endpoint_names = ["export2"]
    enabled        = true
  }

  enrichment {
    key            = "tenant"
    value          = "$twin.tags.Tenant"
    endpoint_names = ["export", "export2"]
  }

  cloud_to_device {
    max_delivery_count = 30
    default_ttl        = "PT1H"
    feedback {
      time_to_live       = "PT1H10M"
      max_delivery_count = 15
      lock_duration      = "PT30S"
    }
  }

  tags = {
    purpose = "testing"
  }
}

#Create IoT Hub Access Policy
resource "azurerm_iothub_shared_access_policy" "hub_access_policy" {
  name                = "terraform-policy"
  resource_group_name = azurerm_resource_group.rg.name
  iothub_name         = azurerm_iothub.iothub.name

  registry_read   = true
  registry_write  = true
  service_connect = true
}

# Create IoT Hub DPS
resource "random_pet" "dps_name" {
  prefix = var.dps_name_prefix
  length = 1
}

resource "azurerm_iothub_dps" "dps" {
  name                = random_pet.dps_name.id
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location
  allocation_policy   = "Hashed"

  sku {
    name     = "S1"
    capacity = 1
  }

  linked_hub {
    connection_string       = azurerm_iothub_shared_access_policy.hub_access_policy.primary_connection_string
    location                = azurerm_resource_group.rg.location
    allocation_weight       = 150
    apply_allocation_policy = true
  }
}

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

variable "resource_group_location" {
  default     = "eastus"
  description = "Location of the resource group."
}

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

variable "eventhub_namespace_name_prefix" {
  default     = "namespace"
  description = "Prefix of the event hub namespace name that's combined with a random ID so name is unique in your Azure subscription."
}

variable "iothub_name_prefix" {
  default     = "iothub"
  description = "Prefix of the iot hub name that's combined with a random ID so name is unique in your Azure subscription."
}

variable "dps_name_prefix" {
  default     = "dps"
  description = "Prefix of the dps name that's combined with a random ID so name is unique in your Azure subscription."
}

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

output "azurerm_iothub_name" {
  value = azurerm_iothub.iothub.name
}

output "azurerm_iothub_dps_name" {
  value = azurerm_iothub_dps.dps.name
}

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

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.

Run az iot dps show to display the Azure DPS resource.

az iot dps show \
   --name <azurerm_iothub_dps_name> \
   --resource-group <resource_group_name>

Key points:

The names of the resource group and the DPS instance display in the terraform apply output. You can also run terraform output to view these output values.

Run Get-AzIoTDeviceProvisioningService to display the Azure DPS resource.

Get-AzIoTDeviceProvisioningService `
      -ResourceGroupName <resource_group_name> `
      -Name <azurerm_iothub_dps_name>

Key points:

The names of the resource group and the DPS instance display in the terraform apply output. You can also run terraform output to view these output values.

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

In this quickstart, you deployed an IoT hub and a Device Provisioning Service instance, and linked the two resources. To learn how to use this setup to provision a device, continue to the quickstart for creating a device.

Quickstart: Provision a simulated symmetric key device

Quickstart: Use Terraform to create an Azure IoT Device Provisioning Service

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

Additional resources