Do not reuse names of deleted Azure Resources

Today I noticed some strange behaviour in the Azure Portal. Of course, it was me to blame 🙂

I was playing around with the usual suspects like IoT Hub, StreamAnalytics, EventHubs, PowerBI, etc.

For some (still unknown) reason, I suddenly did not receive any input from the IoT Hub in StreamAnalytics anymore. I was tampering with registered devices, sending different JSON messages from difference devices using the same identification, who knows.

At a certain point, I decided to delete the IoT Hub. And the deletion takes some time. But I was in a hurry so I immediately created a new IoT Hub. And because this hub is registered by name in StreamAnalytics, I also decided to reuse the name.

Well, still StreamAnalytics was not receiving the supposed telemetry…

And what was even stranger, The new IoT Hub already had received a lot of messages; exactly the same amount as the hub I had just deleted.

So I guess that the Azure portal mixed these two resources up, just because I reused the name. And I also guess that the StreamAnalytics Job was still pointing to the old hub, instead of the brand new one.

Once I deleted the second one, created a third IoT Hub and pointed StreamAnalytics to the third hub, everything was working OK again.

I’m cured, I will not reuse names for Azure resources without waiting a long while.