Need a way to send device modelId

[TahaSnoussi]

Using the SDK, the device is able to announce it's modelId. Each module is also able to announce it's modelId. Can't this be ported to device level with IoT Edge enabled devices?

[varunpuranik]

@TahaSnoussi : Can you please elaborate on what you mean by "Can't this be ported to device level with IoT Edge enabled devices?"? What scenario are you looking to enable?

On IoT Edge devices, the device identity is exposed by the Identity Service to applications running on the device (https://github.com/Azure/iot-identity-service/blob/main/docs/api/identity-service.md#get-iot-device-provisioning-result). But none of the IoT Edge components, or the module workloads supported by IoT Edge use the device identity - they all use their respective module identities.

[TahaSnoussi]

Hello @varunpuranik

The scenario I'm looking to enable is using IoT Plug & Play with an IoT Edge enabled devices. https://docs.microsoft.com/en-us/azure/iot-develop/concepts-developer-guide-device?pivots=programming-language-csharp

Is there a way for an IoT Edge device to announce it's modelId?

[varunpuranik]

@TahaSnoussi :

• As I mentioned before - by default, in IoT Edge, all workload modules use the module identities to connect to IoT Hub. They can expose their modelId (separate for each module)
• If you have a host level workload that uses the device Id, then it can also expose its modelId.
• There is no concept of a uber modelId for all the workloads running on the IoT Edge device - this is because the device has multiple discrete components running on it.
• The IoT Edge runtime components (EdgeAgent/EdgeHub) do not expose their modelId.

Does that answer your question?

[varunpuranik]

@TahaSnoussi - please let me know if you have any further questions. If not can you please close this issue?

[micahl]

@TahaSnoussi are you expecting the device to be connected and managed via IoT Central? Or is this for your own cloud application?

[TahaSnoussi]

@micahl I'm trying to use some features of Plug & Play without using IoT Central. @varunpuranik I'm still trying to find a proper solution to make an IoT Edge Device announce its modelId but from your feedback that's a no go with current implementation. So you can close this issue.

What I implemented for now is the following:

• DPS The enrollement group contains a tag modelId (of the device)
• IoT Hub The device is provisioned with that tag The device sensor module sends telemetry with modelId (of the sensor) to the Hub that is routed to an external event hub
• Digital Twin An Azure Function creates a twin of the device modelId that has sensors as components An Azure Function treats the telemetry to update device twin sensor component that corresponds to that sensor modelId

This way, a Sensor module is represented by a component of a device in digital twin. If I update a sensor to send additional telemetry, I update the model version (in the modelId) and update the device and sensor models in digital twin.

Do you think this is viable?

[micahl]

This way, a Sensor module is represented by a component of a device in digital twin.

@TahaSnoussi would having the Sensor module announce its own modelId not work for your scenario? I'd like to better understand why using a component on the device identity might be preferred to using the module.

[micahl]

@TahaSnoussi I recommend consolidating to a single IoT Edge module that is responsible for reading and transmitting the sensor data. The module could then announce its model ID. That DTDL model might contain multiple components. When/if you add/remove a sensor or change the schema for the expected telemetry then the change is to that single module which is responsible for announcing its model ID after it has been successfully deployed and (I think) avoids the need for using tags like you've described above.