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Tutorial: Perform manual failover for an IoT hub

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Manual failover is a feature of the IoT Hub service that allows customers to failover their hub's operations from a primary region to the corresponding Azure geo-paired region. Manual failover can be done in the event of a regional disaster or an extended service outage. You can also perform a planned failover to test your disaster recovery capabilities, although we recommend using a test IoT hub rather than one running in production. The manual failover feature is offered to customers at no additional cost for IoT hubs created after May 18, 2017.

In this tutorial, you perform the following tasks:

  • Using the Azure portal, create an IoT hub.
  • Perform a failover.
  • See the hub running in the secondary location.
  • Perform a failback to return the IoT hub's operations to the primary location.
  • Confirm the hub is running correctly in the right location.

For more information about manual failover and Microsoft-initiated failover with IoT Hub, see Cross region disaster recovery.

Prerequisites

  • An Azure subscription. If you don't have an Azure subscription, create a free account before you begin.

  • Make sure that port 8883 is open in your firewall. The device sample in this tutorial uses MQTT protocol, which communicates over port 8883. This port may be blocked in some corporate and educational network environments. For more information and ways to work around this issue, see Connecting to IoT Hub (MQTT).

Create an IoT hub

This section describes how to create an IoT hub using the Azure portal.

  1. Sign in to the Azure portal.

  2. On the Azure homepage, select the + Create a resource button.

  3. From the Categories menu, select Internet of Things then IoT Hub.

  4. On the Basics tab, complete the fields as follows:

    • Subscription: Select the subscription to use for your hub.

    • Resource group: Select a resource group or create a new one. To create a new one, select Create new and fill in the name you want to use. To use an existing resource group, select that resource group. For more information, see Manage Azure Resource Manager resource groups.

    • Region: Select the region in which you want your hub to be located. Select the location closest to you. Some features, such as IoT Hub device streams, are only available in specific regions. For these limited features, you must select one of the supported regions.

    • IoT hub name: Enter a name for your hub. This name must be globally unique, with a length between 3 and 50 alphanumeric characters. The name can also include the dash ('-') character.

    Important

    Because the IoT hub will be publicly discoverable as a DNS endpoint, be sure to avoid entering any sensitive or personally identifiable information when you name it.

    Create a hub in the Azure portal.

  5. Select Next: Networking to continue creating your hub.

    Choose the endpoints that devices can use to connect to your IoT hub. You can select the default setting, Public access, or choose Private access. Accept the default setting for this example.

    Choose the endpoints that can connect.

  6. Select Next: Management to continue creating your hub.

    Set the size and scale for a new hub using the Azure portal.

    You can accept the default settings here. If desired, you can modify any of the following fields:

    • Pricing and scale tier: Your selected tier. You can choose from several tiers, depending on how many features you want and how many messages you send through your solution per day. The free tier is intended for testing and evaluation. It allows 500 devices to be connected to the hub and up to 8,000 messages per day. Each Azure subscription can create one IoT hub in the free tier.

      If you are working through a quickstart, select the free tier.

    • IoT Hub units: The number of messages allowed per unit per day depends on your hub's pricing tier. For example, if you want the hub to support ingress of 700,000 messages, you choose two S1 tier units. For details about the other tier options, see Choosing the right IoT Hub tier.

    • Microsoft Defender for IoT: Turn this on to add an extra layer of threat protection to IoT and your devices. This option is not available for hubs in the free tier. Learn more about security recommendations for IoT Hub in Defender for IoT.

    • Role-based access control: Choose how access to the IoT hub is managed, whether shared access policies are allowed or only role-based access control is supported. For more information, see Control access to IoT Hub by using Azure Active Directory.

    • Device-to-cloud partitions: This property relates the device-to-cloud messages to the number of simultaneous readers of the messages. Most hubs need only four partitions.

  7. Select Next: Tags to continue to the next screen.

    Tags are name/value pairs. You can assign the same tag to multiple resources and resource groups to categorize resources and consolidate billing. In this document, you won't be adding any tags. For more information, see Use tags to organize your Azure resources.

    Assign tags for the hub using the Azure portal.

  8. Select Next: Review + create to review your choices. You see something similar to this screen, but with the values you selected when creating the hub.

    Review information for creating the new hub.

  9. Select Create to start the deployment of your new hub. Your deployment will be in progress a few minutes while the hub is being created. Once the deployment is complete, select Go to resource to open the new hub.

Perform a manual failover

Note

There is a limit of two failovers and two failbacks per day for an IoT hub.

  1. Click Resource groups and then select your resource group. Click on your hub in the list of resources.

  2. Under Hub settings on the IoT Hub pane, click Failover.

Screenshot showing IoT Hub properties pane

  1. On the Manual failover pane, you see the Current location and the Failover location. The current location always indicates the location in which the hub is currently active. The failover location is the standard Azure geo-paired region that is paired to the current location. You cannot change the location values. For this tutorial, the current location is West US 2 and the failover location is West Central US.

    Screenshot showing Manual Failover pane

  2. At the top of the Manual failover pane, click Start failover.

  3. In the confirmation pane, fill in the name of your IoT hub to confirm it's the one you want to failover. Then, to initiate the failover, click Failover.

    The amount of time it takes to perform the manual failover is proportional to the number of devices that are registered for your hub. For example, if you have 100,000 devices, it might take 15 minutes, but if you have five million devices, it might take an hour or longer.

    Screenshot showing Manual Failover confirmation pane

    While the manual failover process is running, a banner appears to tell you a manual failover is in progress.

    Screenshot showing Manual Failover in progress

    If you close the IoT Hub pane and open it again by clicking it on the Resource Group pane, you see a banner that tells you the hub is in the middle of a manual failover.

    Screenshot showing IoT Hub failover in progress

    After it's finished, the current and failover regions on the Manual Failover page are flipped and the hub is active again. In this example, the current location is now WestCentralUS and the failover location is now West US 2.

    Screenshot showing failover is complete

    The overview page also shows a banner indicating that the failover is complete and the IoT Hub is running in West Central US.

    Screenshot showing failover is complete in overview page

Perform a failback

After you have performed a manual failover, you can switch the hub's operations back to the original primary region -- this is called a failback. If you have just performed a failover, you have to wait about an hour before you can request a failback. If you try to perform the failback in a shorter amount of time, an error message is displayed.

A failback is performed just like a manual failover. These are the steps:

  1. To perform a failback, return to the Iot Hub pane for your Iot hub.

  2. Under Settings on the IoT Hub pane, click Failover.

  3. At the top of the Manual failover pane, click Start failover.

  4. In the confirmation pane, fill in the name of your IoT hub to confirm it's the one you want to failback. To then initiate the failback, click OK.

    Screenshot of manual failback request

    The banners are displayed as explained in the perform a failover section. After the failback is complete, it again shows West US 2 as the current location and West Central US as the failover location, as set originally.

Clean up resources

To remove the resources you've created for this tutorial, delete the resource group. This action deletes all resources contained within the group. In this case, it removes the IoT hub and the resource group itself.

  1. Click Resource Groups.

  2. Locate and select the resource group ManlFailRG. Click on it to open it.

  3. Click Delete resource group. When prompted, enter the name of the resource group and click Delete to confirm.

Next steps

In this tutorial, you learned how to configure and perform a manual failover, and how to request a failback by performing the following tasks:

  • Using the Azure portal, create an IoT hub.
  • Perform a failover.
  • See the hub running in the secondary location.
  • Perform a failback to return the IoT hub's operations to the primary location.
  • Confirm the hub is running correctly in the right location.

Advance to the next tutorial to learn how to configure your device from a back-end service.

Configure your devices