Find and fix devices missing from Device Update for IoT Hub using agent check

Learn how to use the agent check feature to find, diagnose, and fix devices missing from your Device Update for IoT Hub instance.

Prerequisites

• Access to an IoT Hub with Device Update for IoT Hub enabled.
• An IoT device (or simulator) provisioned for Device Update and reporting a compatible Plug and Play (PnP) model ID.

Note

The agent check feature can only perform validation checks on devices that have the Device Update agent installed and are reporting a PnP model ID that matches those compatible with Device Update for IoT Hub.

Azure portal

Supported browsers:

• Microsoft Edge
• Google Chrome

Azure CLI

An Azure CLI environment:

• Use the Bash environment in Azure Cloud Shell.

  

• Or, if you prefer to run CLI reference commands locally, install the Azure CLI

  1. Sign in to the Azure CLI by using the az login command.
  2. Run az version to find the version and dependent libraries that are installed. To upgrade to the latest version, run az upgrade.
  3. When prompted, install Azure CLI extensions on first use. The commands in this article use the azure-iot extension. Run az extension update --name azure-iot to make sure you're using the latest version of the extension.

Validation checks supported by agent check

The agent check feature currently performs the following validation checks on all devices that meet the above pre-requisites.

Validation check	Criteria
PnP model ID	The PnP model ID is a string that is reported by the Device Update agent to the device twin that describes what PnP model should be used for device/cloud communication. This string must be a valid digital twin model identifier (DTMI) that supports the Device Update interface.
Interface ID	The interface ID is a string that is reported by the Device Update agent to the device twin that describes what Device Update interface version should be used for device/cloud communication. This string must be a valid DTMI that supports the Device Update interface.
Compatibility property names	CompatPropertyNames is a field reported by the Device Update agent to the device twin that describes what deviceProperties fields should be used to determine the device’s compatibility with a given deployment. This field's value must be a string of comma-delimited names. The string must contain at least one and no more than five names. Each name must be <32 characters.
Compatibility property values	Compatibility property values are the field:value pairs specified by the compatPropertyNames field and reported by the Device Update agent to the device twin as deviceProperties. Every name defined in compatibility property names must have a corresponding field:value pair reported. The value for each pair is limited to 64 characters.
ADU group	The ADU Group tag is an optional tag that is defined in the device’s device twin and determines what device group the device belongs to. If specified, the tag string is limited to 255 characters and may only contain alphanumeric characters and the following special characters: "." "-" "_" "~"

If a device fails any of these criteria, it may not show up properly in Device Update. Correcting the invalid value to meet the specified criteria should cause the device to properly appear in Device Update. If the device doesn't show up in Device Update nor in agent check, you may need to run device sync to resolve the issue.

View agent check results

Azure portal

The results of agent check can be found in the diagnostics tab of Device Update.

1. In the Azure portal, navigate to your IoT hub.
2. Select Updates from the navigation menu, then select the Diagnostics tab.
3. Expand the Find missing devices section.

Azure CLI

Use az iot du device health list to view the health of your devices.

The device health list command takes the following arguments:

• --account: The name of the Device Update account.
• --instance: The name of the Device Update instance.
• --filter: A device health filter, either filtering on device state or device ID. For example:
  • To list all healthy devices, filter by state eq 'Healthy'
  • To list all unhealthy devices, filter by state eq 'Unhealthy'
  • To show the health state of a target device, filter by deviceId eq '<device_name>' or deviceId eq '<device_name>' and moduleId eq '<module_name>'

az iot du device health list --account <Device Update account name> --instance <Device Update instance name> --filter "<filter query>"

Initiate a device sync operation

Device sync should be triggered if a device has been registered in IoT hub but isn't showing up in Device Update nor in agent check results.

Only one device sync operation may be active at a time for each Device Update instance.

Azure portal

1. In the Azure portal, navigate to your IoT hub.
2. Select Updates from the navigation menu, then select the Diagnostics tab.
3. Expand the View device health section.
4. Select Start a device sync.

Azure CLI

Use az iot du device import to import devices and modules to the Device Update instance from a linked IoT hub.

az iot du device import --account <Device Update account name> --instance <Device Update instance name>

Next steps

To learn more about Device Update's diagnostic capabilities, see Device update diagnostic feature overview