Testing Azure IoTHub Manual failover

The Azure IoTHub is the center of all the IoT efforts of Microsoft. Over the last couple of years (or even months) we see a lot of innovations from that side.

The latest addition is the Manual failover which is now in preview.

This makes it possible to move a complete IoTHub (with eg. all of its devices and routes) to the ‘sister region’. For example, an IoTHub living in West US 2 will move to West Central US. And you can move it back too.

The manual failover is a good starting point for having a more resilient IoTHub. It’s not perfect, there is a chance that unread messages or data is lost. Failover is hard:

But it’s a perfect way to test the ‘automatic’ failover which Microsoft provides when something happens with the region your IoTHub is living in.

I wanted to test this failover. And I wanted to build a client-side solution so I would not lose any messages.

Let’s see how it can be tested.

How to tag your IoT Hub Devices

Until now, device twin tags were a bit lame.

Yes, desired and reported properties were much more fun to play with.

But those of you who administer thousands of Azure IoT devices, you really appreciate tags. It’s the only way to control that large amount of devices without losing your head.

Why? Because you first query your devices and then execute jobs on these subsets.

And Microsoft is making use of this feature a lot. You will have to use tags if you want to execute IoT Edge deployments (still in preview) or if you want to use the recently added Automatic Device Management (even newer):

But how do you actually add or alter tags of devices? What tooling is Microsoft providing?

Let’s check out a number of ways to tag and start querying your devices.