Deleted Azure Event Hub is automatically re-created by Azure Diagnostic Settings

Summary

This article provides a solution to an issue where Azure Diagnostic Settings or their configuration cache automatically re-creates a deleted Azure Event Hub.

Symptoms

You might see the following symptoms:

• When you delete an event hub from an Event Hubs namespace, the event hub is automatically re-created by the data flowing into it through the diagnostic settings.
• After you delete an event hub and all diagnostic settings configured to send data to it, the event hub is automatically re-created.

Cause

Here are the causes of the issue:

• When you configure a diagnostic setting to send data to an Azure event hub, if the diagnostic setting receives an error message that indicates that the event hub doesn't exist, it tries to create the event hub, and then continues trying to send the data.
• Azure diagnostic settings maintain a cache of configurations for approximately one hour. Even if you remove the diagnostic settings, they continue to send data to the destination (such as a deleted event hub) during this period. This action causes the event hub to be re-created.

Solution

If you delete an event hub from an Event Hubs namespace, use one of the following methods to resolve the issue:

• Update the diagnostic settings to stop sending data to the event hub.
• Delete the diagnostic settings.

If you delete an event hub and related diagnostic settings, use the following method to resolve the issue:

• Update the diagnostic settings to stop sending data to the event hub, delete them, wait at least one hour to allow their configuration cache to expire, and then delete the event hub.