Automatic Device Management with Device Twins in Azure

Configure Cloud Shell

1. Access Azure Cloud Shell using the credentials provided in the lab.
2. Choose the Bash environment.
3. Select Show advanced settings.
4. Use the existing storage account that resides in the resource group location and the existing cloudshell file share name.
5. Install the Azure IoT extension for CLI:

   az extension add --name azure-iot
   

Register and Configure the IoT device

The following steps are configured with the CLI in Cloud Shell. Note that XXXXX is the five-character suffix for the lab resources.

1. Register the device in the IoT Hub identity registry:

   az iot hub device-identity create --device-id IoTDevice1 --hub-name iothub-XXXXX
   

2. Obtain the connection string for the device application:

   az iot hub device-identity connection-string show --hub-name iothub-XXXXX --device-id IoTDevice1 --output table
   

3. Copy the connection string to your clipboard and paste it into a text document.

4. Add tags to the IoT device twin:

   az iot hub device-twin update --device-id IoTDevice1 --hub-name iothub-ycb3m --set tags='{"location":{"state":"TX","city":"Austin"}}'
   

Create the IoT device management configuration

The following steps will be configured in the Azure Portal. Note that XXXXX is the five-character suffix for the lab resources.

1. Access the Azure Portal using the credentials provided in the lab.
2. Click on the IoT Hub provisioned for this lab. It will be named IoTHub-XXXXX.
3. Click on IoT device configuration in the IoTHub-XXXXX pane.
4. Click + Add Device Configuration to create the configuration with the following settings:
   • Name and Label: - Name: This is descriptive, so name it anything. It has to be lowercase and the only special characters that can be used are '-+%_\*. - Labels: You can specify a key/tag pair for this configuration, but it is not required.
     • Twin Settings:
       • Device Twin Property: Use properties.desired.settings.
       • Device Twin Property Content: Use { "gatelocked": false, "gateclosed": false }.
     • Metrics:
       • Metric Name: Use nowReporting.
       • Metric Criteria: Use SELECT deviceId FROM devices WHERE properties.reported.settings.status = 'Success'
     • Target Devices:.
       • Priority: Use 10.
       • Target Condition: Use tags.location.city = 'Austin'.

Click Review + create and then Create to create the deployment.

Verify That the Configuration Was Applied

Once the configuration has been created, verify that it has been deployed to the test device.

1. Click on IoT devices in the IoTHub-XXXXX pane and click on the device created in the first objective.
2. Click on Device Twin to view the twin. Verify that the desired properties now reside within the twin.

1. Access Azure Cloud Shell using the credentials provided in the lab.

2. Download the sample Node.js application by cloning the Git repository for this course:

   git clone https://github.com/linuxacademy/content-AZ-220.git
   

3. Change to the directory for the Device Twin lab:

   cd content-AZ-220/samples/DeviceTwins/
   

4. Install the Node dependencies for the sample application:

   npm install
   

5. Modify test_device_twins.js in vi or nano, replacing <device-id> on line 6 with the device connection string copied in Objective 1.

The sample node application acts as a simulated device. It reads the desired properties from the device twin and "sets" the properties as reported. This is how we use device twins to synchronize desired properties (from the back-end application) with the reported properties (from the Iot Devices).

To run the application, type the following in Cloud Shell:

node test_device_twins.js

There will be output regarding the progress of the application. Once the application has reported successful changes, it may be exited by pressing CTRL+C.

Verify That the Reported Properties Were Applied

Verify that the desired properties are now reported properties in the device twin:

1. Click on IoT devices in the IoTHub-XXXXX pane, then click on the device created in the first objective.
2. Click on Device Twin to view the twin. Verify that the reported properties now reside within the twin.