How to create Azure IoT Module Identities via DPS

For those working with Azure IoT Edge, the support for Azure IoT Edge modules is a well-known mechanism to deploy pieces of IoT logic to (edge) devices.

Every Azure IoT Edge module functions as a Docker container with an independent message flow, module twin, tags, desired properties, reported properties, and direct methods.

The modules are bound to the Azure IoT Edge device and rely on the security and communication channel provided by that device registration.

Azure IoT also supports the concept of Module Identities.

This ability is less known and used, which is a pity if you consider all the options it brings…

Module Identities are registered as part of any Azure IoT device. This can be an edge device but it also works for ‘generic’ Azure IoT devices.

Module Identities have their own credentials, something an Azure IoT Edge module does not have.

This way, Module Identities can send their own messages, have a module twin, and support direct methods.

Why should we use Module Identities?

If you consider your devices as being modular by design, with different parts of data collection, perhaps even by different manufacturers, you can separate concerns and security by giving each part its own module identity. It even fits well into Azure IoT Plug&Play.

Unfortunately, the Device Provisioning Service does not support Module Identities, only Device Identities. I expect this is why Module Identities never became as popular as it should be.

But this is not the end of the story…

Let’s see how we can work around this shortcoming.

IoT Edge group enrollments using symmetric keys

In my previous blog about using a VM as IoT Edge device, it became clear that this could be used for testing IoT Edge at scale.

Testing IoT Edge at scale means testing device enrollments using the Device Provisioning Service (DPS) and IoT Hub deployments at scale.

We will look at both situations. But before we check out a group enrollment, first we look at an individual enrollment, just for comparison.

We will use the recently announced IoT Edge support for symmetric keys in DPS.

Connecting simple devices to IoT Central

Once you start collecting data in an IoT solution, you will need some kind of dashboard to represent the raw or aggregated data.

IoT projects typically start as a POC to validate IoT scenarios. When the POC success, a pilot project is started to check scalability, monitoring, maintainability, etc.

Microsoft provides multiple solutions for these various scenarios. The most lightweight solution is IoT Central.

“Experience the simplicity of SaaS for IoT (Internet of Things), with no cloud expertise required—Azure IoT Central is a fully managed global IoT SaaS (software-as-a-service) solution that makes it easy to connect, monitor, and manage your IoT assets at scale. Bring your connected products to market faster while staying focused on your customers.”

You can start with a 7-day trial or with pay-as-you-go. This last option is free if you limit yourself to 5 actual or simulated devices.

At this moment, Microsoft has examples for the Raspberry Pi, the MX Chip IoT Devkit and Windows 10 IoT Core.

But what if you want to connect your own device? Is this simple to do too?

Let’s check this out.