Create and provision IoT Edge for Linux on Windows devices at scale using symmetric keys

Article
03/27/2024

Applies to: IoT Edge 1.4

Important

IoT Edge 1.4 is the supported release. If you are on an earlier release, see Update IoT Edge.

This article shows how to autoprovision one or more IoT Edge for Linux on Windows devices using symmetric keys. You can automatically provision Azure IoT Edge devices with the Azure IoT Hub device provisioning service (DPS). If you're unfamiliar with the process of autoprovisioning, review the provisioning overview before continuing.

The tasks are as follows:

Create either an individual enrollment for a single device or a group enrollment for a set of devices.
Deploy a Linux virtual machine with the IoT Edge runtime installed and connect it to the IoT Hub.

Symmetric key attestation is a simple approach to authenticating a device with a device provisioning service instance. This attestation method represents a "Hello world" experience for developers who are new to device provisioning, or do not have strict security requirements. Device attestation using a TPM or X.509 certificates is more secure, and should be used for more stringent security requirements.

Prerequisites

Cloud resources

An active IoT hub
An instance of the IoT Hub device provisioning service in Azure, linked to your IoT hub
- If you don't have a device provisioning service instance, you can follow the instructions in the Create a new IoT Hub device provisioning service and Link the IoT hub and your device provisioning service sections of the IoT Hub device provisioning service quickstart.
- After you have the device provisioning service running, copy the value of ID Scope from the overview page. You use this value when you configure the IoT Edge runtime.

Device requirements

A Windows device with the following minimum requirements:

System Requirements
- Windows 10¹/11 (Pro, Enterprise, IoT Enterprise)
- Windows Server 2019¹/2022
  _{¹ Windows 10 and Windows Server 2019 minimum build 17763 with all current cumulative updates installed.}
Hardware requirements
- Minimum Free Memory: 1 GB
- Minimum Free Disk Space: 10 GB
Virtualization support
- On Windows 10, enable Hyper-V. For more information, see Install Hyper-V on Windows 10.
- On Windows Server, install the Hyper-V role and create a default network switch. For more information, see Nested virtualization for Azure IoT Edge for Linux on Windows.
- On a virtual machine, configure nested virtualization. For more information, see nested virtualization.
Networking support
- Windows Server does not come with a default switch. Before you can deploy EFLOW to a Windows Server device, you need to create a virtual switch. For more information, see Create virtual switch for Linux on Windows.
- Windows Desktop versions come with a default switch that can be used for EFLOW installation. If needed, you can create your own custom virtual switch.

Tip

If you want to use GPU-accelerated Linux modules in your Azure IoT Edge for Linux on Windows deployment, there are several configuration options to consider.

You will need to install the correct drivers depending on your GPU architecture, and you may need access to a Windows Insider Program build. To determine your configuration needs and satisfy these prerequisites, see GPU acceleration for Azure IoT Edge for Linux on Windows.

Make sure you take the time to satisfy the prerequisites for GPU acceleration now. You will need to restart the installation process if you decide you want GPU acceleration during installation.

Developer tools

Prepare your target device for the installation of Azure IoT Edge for Linux on Windows and the deployment of the Linux virtual machine:

Set the execution policy on the target device to AllSigned. You can check the current execution policy in an elevated PowerShell prompt using the following command:
```
Get-ExecutionPolicy -List
```
If the execution policy of local machine is not AllSigned, you can set the execution policy using:
```
Set-ExecutionPolicy -ExecutionPolicy AllSigned -Force
```

For more information on the Azure IoT Edge for Linux on Windows PowerShell module, see the PowerShell functions reference.

Create a DPS enrollment

Create an enrollment to provision one or more devices through DPS.

If you are looking to provision a single IoT Edge device, create an individual enrollment. If you need multiple devices provisioned, follow the steps for creating a DPS group enrollment.

When you create an enrollment in DPS, you have the opportunity to declare an initial device twin state. In the device twin, you can set tags to group devices by any metric you need in your solution, like region, environment, location, or device type. These tags are used to create automatic deployments.

For more information about enrollments in the device provisioning service, see How to manage device enrollments.

Individual enrollment
Group enrollment

Create a DPS individual enrollment

Tip

The steps in this article are for the Azure portal, but you can also create individual enrollments using the Azure CLI. For more information, see az iot dps enrollment. As part of the CLI command, use the edge-enabled flag to specify that the enrollment is for an IoT Edge device.

In the Azure portal, navigate to your instance of IoT Hub device provisioning service.
Under Settings, select Manage enrollments.
Select Add individual enrollment then complete the following steps to configure the enrollment:
1. For Mechanism, select Symmetric Key.
2. Provide a unique Registration ID for your device.
3. Optionally, provide an IoT Hub Device ID for your device. You can use device IDs to target an individual device for module deployment. If you don't provide a device ID, the registration ID is used.
4. Select True to declare that the enrollment is for an IoT Edge device.
5. Optionally, add a tag value to the Initial Device Twin State. You can use tags to target groups of devices for module deployment. For example:
```
{
   "tags": {
      "environment": "test"
   },
   "properties": {
      "desired": {}
   }
}
```
6. Select Save.
Copy the individual enrollment's Primary Key value to use when installing the IoT Edge runtime.

Now that an enrollment exists for this device, the IoT Edge runtime can automatically provision the device during installation.

Create a DPS group enrollment

Tip

The steps in this article are for the Azure portal, but you can also create group enrollments using the Azure CLI. For more information, see az iot dps enrollment-group. As part of the CLI command, use the edge-enabled flag to specify that the enrollment is for IoT Edge devices. For a group enrollment, all devices must be IoT Edge devices or none of them can be.

In the Azure portal, navigate to your instance of IoT Hub device provisioning service.
Under Settings, select Manage enrollments.
Select Add individual enrollment then complete the following steps to configure the enrollment:
1. Provide a Group name.
2. Select Symmetric Key as the attestation type.
3. Select True to declare that the enrollment is for an IoT Edge device. For a group enrollment, all devices must be IoT Edge devices or none of them can be.
4. Optionally, add a tag value to the Initial Device Twin State. You can use tags to target groups of devices for module deployment. For example:
```
{
   "tags": {
      "environment": "test"
   },
   "properties": {
      "desired": {}
   }
}
```
5. Select Save.
Copy your enrollment group's Primary Key value to use when creating device keys for use with a group enrollment.

Now that an enrollment group exists, the IoT Edge runtime can automatically provision devices during installation.

Derive a device key

Each device that is provisioned as part of a group enrollment needs a derived device key to perform symmetric key attestation with the enrollment during provisioning.

To generate a device key, use the key that you copied from your DPS enrollment group to compute an HMAC-SHA256 of the unique registration ID for the device and convert the result into Base64 format.

Important

Do not include your enrollment's primary or secondary key in your device code.

On Windows, you can use PowerShell to generate your derived device key as shown in the following example.

Replace the value of KEY with the Primary Key you noted earlier.

Replace the value of REG_ID with your device's registration ID.

$KEY='PASTE_YOUR_ENROLLMENT_KEY_HERE'
$REG_ID='PASTE_YOUR_REGISTRATION_ID_HERE'

$hmacsha256 = New-Object System.Security.Cryptography.HMACSHA256
$hmacsha256.key = [Convert]::FromBase64String($KEY)
$sig = $hmacsha256.ComputeHash([Text.Encoding]::ASCII.GetBytes($REG_ID))
$derivedkey = [Convert]::ToBase64String($sig)
echo "`n$derivedkey`n"

Below is a sample output of a derived device key:

Jsm0lyGpjaVYVP2g3FnmnmG9dI/9qU24wNoykUmermc=

Install IoT Edge

Deploy Azure IoT Edge for Linux on Windows on your target device.

Note

The following PowerShell process outlines how to deploy IoT Edge for Linux on Windows onto the local device. To deploy to a remote target device using PowerShell, you can use Remote PowerShell to establish a connection to a remote device and run these commands remotely on that device.

In an elevated PowerShell session, run either of the following commands depending on your target device architecture to download IoT Edge for Linux on Windows.

X64/AMD64

$msiPath = $([io.Path]::Combine($env:TEMP, 'AzureIoTEdge.msi'))
$ProgressPreference = 'SilentlyContinue'
Invoke-WebRequest "https://aka.ms/AzEFLOWMSI_1_4_LTS_X64" -OutFile $msiPath

ARM64

$msiPath = $([io.Path]::Combine($env:TEMP, 'AzureIoTEdge.msi'))
$ProgressPreference = 'SilentlyContinue'
Invoke-WebRequest "https://aka.ms/AzEFLOWMSI_1_4_LTS_ARM64" -OutFile $msiPath

Install IoT Edge for Linux on Windows on your device.
```
Start-Process -Wait msiexec -ArgumentList "/i","$([io.Path]::Combine($env:TEMP, 'AzureIoTEdge.msi'))","/qn"
```
You can specify custom IoT Edge for Linux on Windows installation and VHDX directories by adding INSTALLDIR="<FULLY_QUALIFIED_PATH>" and VHDXDIR="<FULLY_QUALIFIED_PATH>" parameters to the install command. For example, if you want to use the D:\EFLOW folder for installation and the D:\EFLOW-VHDX for the VHDX, you can use the following PowerShell cmdlet.
```
Start-Process -Wait msiexec -ArgumentList "/i","$([io.Path]::Combine($env:TEMP, 'AzureIoTEdge.msi'))","/qn","INSTALLDIR=D:\EFLOW", "VHDXDIR=D:\EFLOW-VHDX"
```
Set the execution policy on the target device to AllSigned if it is not already. See the PowerShell prerequisites for commands to check the current execution policy and set the execution policy to AllSigned.
Create the IoT Edge for Linux on Windows deployment. The deployment creates your Linux virtual machine and installs the IoT Edge runtime for you.
```
Deploy-Eflow
```
Tip

By default, the Deploy-Eflow command creates your Linux virtual machine with 1 GB of RAM, 1 vCPU core, and 16 GB of disk space. However, the resources your VM needs are highly dependent on the workloads you deploy. If your VM does not have sufficient memory to support your workloads, it will fail to start.

You can customize the virtual machine's available resources using the Deploy-Eflow command's optional parameters. This is required to deploy EFLOW on a device with the minimum hardware requirements.

For example, the command below creates a virtual machine with 1 vCPU core, 1 GB of RAM (represented in MB), and 2 GB of disk space:
```
Deploy-Eflow -cpuCount 1 -memoryInMB 1024 -vmDataSize 2
```
For information about all the optional parameters available, see PowerShell functions for IoT Edge for Linux on Windows.
Warning

By default, the EFLOW Linux virtual machine has no DNS configuration. Deployments using DHCP will try to obtain the DNS configuration propagated by the DHCP server. Please check your DNS configuration to ensure internet connectivity. For more information, see AzEFLOW-DNS.

You can assign a GPU to your deployment to enable GPU-accelerated Linux modules. To gain access to these features, you will need to install the prerequisites detailed in GPU acceleration for Azure IoT Edge for Linux on Windows.

To use a GPU passthrough, add the gpuName, gpuPassthroughType, and gpuCount parameters to your Deploy-Eflow command. For information about all the optional parameters available, see PowerShell functions for IoT Edge for Linux on Windows.

Warning

Enabling hardware device passthrough may increase security risks. Microsoft recommends a device mitigation driver from your GPU's vendor, when applicable. For more information, see Deploy graphics devices using discrete device assignment.
Enter 'Y' to accept the license terms.
Enter 'O' or 'R' to toggle Optional diagnostic data on or off, depending on your preference.
Once the deployment is complete, the PowerShell window reports Deployment successful.

After a successful deployment, you are ready to provision your device.

Provision the device with its cloud identity

Once the runtime is installed on your device, configure the device with the information it uses to connect to the device provisioning service and IoT Hub.

Have the following information ready:

The DPS ID Scope value
The device Registration ID you created
Either the Primary Key from an individual enrollment, or a derived key for devices using a group enrollment.

Run the following command in an elevated PowerShell session with the placeholder values updated with your own values:

Provision-EflowVm -provisioningType DpsSymmetricKey -scopeId PASTE_YOUR_ID_SCOPE_HERE -registrationId PASTE_YOUR_REGISTRATION_ID_HERE -symmKey PASTE_YOUR_PRIMARY_KEY_OR_DERIVED_KEY_HERE

Verify successful installation

Verify that IoT Edge for Linux on Windows was successfully installed and configured on your IoT Edge device.

Individual enrollment
Group enrollment

You can verify that the individual enrollment that you created in device provisioning service was used. Navigate to your device provisioning service instance in the Azure portal. Open the enrollment details for the individual enrollment that you created. Notice that the status of the enrollment is assigned and the device ID is listed.

Log in to your IoT Edge for Linux on Windows virtual machine using the following command in your PowerShell session:
```
Connect-EflowVm
```
Note

The only account allowed to SSH to the virtual machine is the user that created it.
Once you are logged in, you can check the list of running IoT Edge modules using the following Linux command:
```
sudo iotedge list
```
If you need to troubleshoot the IoT Edge service, use the following Linux commands.
1. Retrieve the service logs.
```
sudo iotedge system logs
```
2. Use the check tool to verify configuration and connection status of the device.
```
sudo iotedge check
```
Note

On a newly provisioned device, you may see an error related to IoT Edge Hub:

× production readiness: Edge Hub's storage directory is persisted on the host filesystem - Error

Could not check current state of edgeHub container

This error is expected on a newly provisioned device because the IoT Edge Hub module isn't running. To resolve the error, in IoT Hub, set the modules for the device and create a deployment. Creating a deployment for the device starts the modules on the device including the IoT Edge Hub module.

When you create a new IoT Edge device, it will display the status code 417 -- The device's deployment configuration is not set in the Azure portal. This status is normal, and means that the device is ready to receive a module deployment.

Uninstall IoT Edge for Linux on Windows

If you want to remove the Azure IoT Edge for Linux on Windows installation from your device, use the following commands.

Open Settings on Windows
Select Add or Remove Programs
Select Azure IoT Edge app
Select Uninstall

Next steps

The device provisioning service enrollment process lets you set the device ID and device twin tags at the same time as you provision the new device. You can use those values to target individual devices or groups of devices using automatic device management. Learn how to Deploy and monitor IoT Edge modules at scale using the Azure portal or using Azure CLI.

You can also:

Continue to deploy IoT Edge modules to learn how to deploy modules onto your device.
Learn how to manage certificates on your IoT Edge for Linux on Windows virtual machine and transfer files from the host OS to your Linux virtual machine.
Learn how to configure your IoT Edge devices to communicate through a proxy server.