Introduction

10 minutes

Run an IoT edge device in restricted network and offline

Azure IoT Edge supports extended offline operations on IoT Edge devices, and also enables offline operations on non-IoT Edge child devices. The IoT Edge device and any connected child devices can continue to function with intermittent or no internet connection as long as the IoT Edge device has had one opportunity to connect to IoT Hub.

The IoT Edge hub takes on three roles when an IoT Edge device goes into offline mode. First, it stores any upstream messages and saves them until the device reconnects. Second, it acts on behalf of IoT Hub to authenticate modules and child devices so that they can continue to operate. Third, it enables communication between child devices that normally would go through IoT Hub.

Learning objectives

In this module you will:

Verify Lab Prerequisites
Create an IoT Hub and Device ID
Deploy Azure IoT Edge Enabled Linux VM
Setup an IoT Edge Parent with Child IoT Devices
Configure IoT Edge Device as Gateway
Open IoT Edge Gateway Device Inbound Ports using Azure CLI
Configure IoT Edge Device Time-to-Live and Message Storage
Connect Child IoT Device to IoT Edge Gateway
Test Device Connectivity and Offline Support

Prerequisites

An introductory knowledge of the purpose of Azure IoT
Ability to navigate Azure IoT portal
Ability to use Node.js, or C#, at the beginner level
Experience using Visual Studio, or Visual Studio Code, at the beginner level

This lab assumes the following resources are available:

Resource Group -- AZ-220-RG
IoT Hub -- AZ-220-HUB-{YOUR-ID}
IoT Device -- SimulatedThermostat

Execute the lab-setup.azcli script before starting the lab if the resources are unavailable.

Note

You will need the SimulatedDevice connection string. You can obtain that by running the following command in the Azure Cloud Shell

az iot hub device-identity connection-string show --hub-name AZ-220-HUB-_{YOUR-ID}_ --device-id SimulatedThermostat -o tsv

The scenario

Retailer Tailwind Trader's conveyor belt system monitors vibrations, telemetry, and counts objects. They want their system to be resilient to network outages and also optimize the bulk upload of telemetry data at specific times in the day (load balancing network usage). Your job will be to configure IoT Edge to support offline in case network drops and look into storing telemetry from sensors locally and configure for regular syncs at given times.

In this module, you will learn the different scenarios where IoT Edge device is on an enterprise network (needs proxy settings) or needs extended offline capabilities to address the scenario above

Task 1: Execute setup script

If necessary, log in to your Azure portal using your Azure account credentials. If you have more than one Azure account, be sure that you are logged in with the account that is tied to the subscription that you will be using for this course.
Open the Azure Cloud Shell by clicking the Terminal icon within the top header bar of the Azure portal, and select the Bash shell option.
Before the Azure CLI can be used with commands for working with Azure IoT Hub, the Azure IoT Extensions need to be installed. To install the extension, run the following command:
```
 az extension add --name azure-cli-iot-ext
```
To upload the setup script, in the Azure Cloud Shell toolbar, click Upload/Download files (fourth button from the right).
In the dropdown, select Upload and in the file selection dialog, navigate to the lab-setup.azcli file for this lab. Select the file and click Open to upload it.

A notification will appear when the file upload has completed.
You can verify that the file has uploaded by listing the content of the current directory by entering the ls command.
To create a directory for this lab, move lab-setup.azcli into that directory, and make that the current working directory, enter the following commands:
```
 mkdir lab14
 mv lab-setup.azcli lab14
 cd lab14
```
To ensure the lab-setup.azcli has the execute permission, enter the following commands:
```
 chmod +x lab-setup.azcli
```
To edit the lab-setup.azcli file, click { } (Open Editor) in the toolbar (second button from the right). In the Files list, select lab14 to expand it and then select lab-setup.azcli.

The editor will now show the contents of the lab-setup.azcli file.

In the editor, update the values of the {YOUR-ID} and Location variables. Set {YOUR-ID} to the Unique ID you created at the start of this course - i.e. CP123019, and set Location to the location that makes sense for your resources.

Note

The Location variable should be set to the short name for the location. You can see a list of the available locations and their short-names (the Name column) by entering this command:

az account list-locations -o Table

DisplayName           Latitude    Longitude    Name
--------------------  ----------  -----------  ------------------
East Asia             22.267      114.188      eastasia
Southeast Asia        1.283       103.833      southeastasia
Central US            41.5908     -93.6208     centralus
East US               37.3719     -79.8164     eastus
East US 2             36.6681     -78.3889     eastus2

To save the changes made to the file and close the editor, click … in the top-right of the editor window and select Close Editor.

Click Save and the editor will close if prompted to save.

Note

You can use CTRL+S to save at any time and CTRL+Q to close the editor.
To create a resource group named AZ-220-RG, create an IoT Hub named AZ-220-HUB-{YourID}, add a device with a Device ID of SimulatedThermostat, and display the device connection string, enter the following command:
```
 ./lab-setup.azcli
```
The script will take a few minutes to run. You will see JSON output as each step completes.
Once complete, the connection string for the device, starting with “HostName=”, is displayed. Copy this connection string into a text document and note that it is for the SimulatedThermostat device.

Continue

Learning objectives

Prerequisites

The scenario

Task 1: Execute setup script

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