Understand namespace assets and devices

Azure IoT Operations uses the terms namespace asset and device to refer to configuration resources. These configuration resources don't map directly to the physical assets and devices in your environment. Instead, they define how a connector in Azure IoT Operations connects to and interacts with the physical assets and devices in your environment. In Azure IoT Operations:

• A device (preview) is a configuration resource that encapsulates the connection information required to connect to one or more physical devices or assets.
• A namespace asset (preview) is a configuration resource that encapsulates information about the data that a physical asset or device exchanges with IoT Operations.

These configuration resources are stored as Kubernetes custom resources and as entries in the Azure Device Registry.

This diagram shows the relationships between namespace assets, devices, and connector templates. This article describes these resources in more detail.

Devices

Before you create an asset, define a device. A device is a configuration resource that describes southbound edge connectivity information for one or more namespace assets. Each device has one or more inbound endpoints that define how the device connects securely to a physical asset or device. For example:

• A device with an inbound endpoint definition for OPC UA stores the information you need to connect to an OPC UA server.
• A device with an inbound endpoint definition for the media connector stores the information you need to connect to a media source.

Inbound endpoints

An inbound endpoint configuration defines how a device connects to a physical asset or device. Each inbound endpoint has properties like:

• Address: The network address of the physical asset or device. For example, the URL of an OPC UA server or the IP address of a camera.
• Connector type: The type of connector the device uses to connect to the physical asset or device. For example, opcua, onvif, or media.
• Authentication data: The credentials the device uses to authenticate to the physical asset or device. For example, a username and password.

Connector templates

Connector templates define the types of inbound endpoints available to OT users. For example, the ONVIF connector template defines the properties required to create an inbound endpoint that connects to an ONVIF-compliant camera.

An IT user adds connector templates in the Azure portal. After the IT user adds a connector template, an OT user can create devices with inbound endpoints of that type in the operations experience web UI.

Namespace assets

A namespace asset is a configuration resource that represents a physical device or asset as an Azure Resource Manager resource in the cloud and as a Kubernetes custom resource at the edge. When you define a namespace asset using the operations experience or Azure IoT Operations CLI, set up schema information like data points, tags, events, and streams for each asset.

The type of inbound endpoint that the namespace asset connects to determines what schema elements you define for the asset. For example, if the namespace asset connects to an OPC UA server, define tags and events. If the namespace asset connects to a media resource, define streams.

Tags

A tag is a value that an OPC UA server emits. For example, OPC UA tags give real-time or historical data about a physical asset connected to the OPC UA server.

Tags are grouped into datasets. A dataset is a collection of tags that are logically related. The dataset specifies the MQTT topic where the asset publishes tag values.

Streams

A stream is streaming data, like video or image snapshots from a media source. For example, a camera connected to the media connector can stream video data.

Streams can be:

• Published to an MQTT topic
• Saved to storage and synced with the cloud
• Routed to a media service

Events

An event is a notification of a state change to your OPC UA and ONVIF assets. For example, a physical asset connected to an OPC UA server can generate an event when a temperature reaches a certain threshold.

Events are grouped into event groups. An event group is a collection of events that are logically related. The event group specifies the MQTT topic where the asset publishes event data.

Actions

An action is a command that you send to an ONVIF asset. For example, you can send an action to a camera to start recording video.

Actions are grouped into management groups. A management group is a collection of actions that are logically related. The management group specifies the MQTT topic where the asset subscribes for action commands.

Data points

A data point is a single piece of information that's fetched from an HTTP/REST endpoint. For example, a temperature reading from a sensor is a data point.

Data points are grouped into datasets. A dataset is a collection of data points that are logically related. The dataset specifies the MQTT topic where the asset publishes tag values.

Destinations

Namespace assets don't provide northbound connectivity for physical assets and devices. They publish data to the MQTT broker or save data to local storage. Other Azure IoT Operations services provide northbound connectivity. For example:

• Data flows route data from the MQTT broker to cloud services like Azure Event Grid or Azure Event Hubs.
• The media connector proxies media streams to other media servers or uploads captured data to Azure blob storage.