Event Hub: seeing requests but no messages

Quattrocchi, Calogero 265

Hello,

We have an Event Hub namespace set up but we can see successful/incoming requests without any messages or throughput. Why is this happening?

Thanks.

Regards.

phemanth 10,740 Reputation points Microsoft Vendor

2024-09-24T13:20:50.2333333+00:00

@Quattrocchi, Calogero

Thanks for reaching out to Microsoft Q&A

please check the below steps

Message Formatting: Ensure that the messages being sent to the Event Hub are correctly formatted. Incorrectly formatted messages might be rejected silently.

Client Configuration: Double-check the configuration of your Event Hub client. Make sure the connection string and Event Hub name are correct.

Authorization: Verify that the sending application has the necessary permissions to send messages to the Event Hub.

Quota Limits: Check if you’ve hit any quota limits for your Event Hub namespace. This can sometimes prevent messages from being processed.

Network Issues: Ensure there are no network issues preventing messages from being sent to the Event Hub.

Event Hub Status: Sometimes, creating a new Event Hub within the same namespace can resolve the issue.

For more detailed troubleshooting steps, you can refer to the Azure Event Hubs troubleshooting guide.

Hope this helps. Do let us know if issue persists.
Sander van de Velde | MVP 32,726 Reputation points MVP

2024-09-25T06:28:30.6733333+00:00

Hello @Quattrocchi, Calogero,

welcome to this moderated Azure community forum.

Better questions with more information lead to better answers from our community members.

Please provide information about the steps you have taken, the guide you follow, and the describe the situation so fellow members can understand your question better.

You see just one request or several, continuous requests appear on your EventHub?

Is the EventHub just created or did you attach some publisher already (is there a publisher service in place having access to the EventHub)?
Quattrocchi, Calogero 265 Reputation points

2024-09-25T07:03:02.0233333+00:00
Hi,

Sorry and let me put a bit more context. We have deployed one Event Hub namespace with one event hub through ARM Teamplate.

The networking settings of the EVH namespace are set as follows:

Public network access: DISABLED

Allow trusted Microsoft services to bypass this firewall? YES

Although the Event hub is actually not used for the moment, we can see some requests appearing the Overview.

The question is more what is the source of those requests?

Microsoft Services doing some checks?

Many thanks.

Regards.
Sander van de Velde | MVP 32,726 Reputation points MVP

2024-09-25T12:52:33.9433333+00:00

Hello @Quattrocchi, Calogero,

thanks for describing the situation.

My expectations is that the EventHub ingest is being tested by the underlying Azure infrastructure/resources.

Can you add a listener or EventHub explorer on the EventHub to see the incoming messages?
Quattrocchi, Calogero 265 Reputation points

2024-09-25T14:20:35.68+00:00

Indeed, I also imagine that Azure services/resources are accessing the event hub.

Thanks for the suggestion but how to add a listener on the Event Hub?

Thanks

Accepted answer

Sander van de Velde | MVP 32,726 Reputation points MVP

2024-09-26T19:35:17.2833333+00:00

Hello @Quattrocchi, Calogero,

welcome to this moderated Azure community forum.

Regarding the 'ghost' messages, I checked it myself when I created a new Event Hub.

I too experienced new messages:

The Event Hub has a built-in way to see queued messages, look for "Process data" in the menu:

Be aware a consumer group is created for this viewer. A 'basic' Event Hub only support the creatino of one consumer group:

A StreamAnalytics-like dashboard is show, normally showing ingested data.

But you probably get a messagebox like this:

I expect these messages are used to test the connection (also seen when an Stream Analytics Job output is created and you hit the Test button). These messages are then filtered out.

If the response helped, do "Accept Answer". If it doesn't work, please let us know the progress. All community members with similar issues will benefit by doing so. Your contribution is highly appreciated.
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Quattrocchi, Calogero 265 Reputation points

2024-09-27T07:12:36.8566667+00:00

Hi, thanks for your answer.

Indeed, when you choose "Enable real time insights from events", you get the Test query:

SELECT * INTO [OutputAlias] FROM [eventhubinstancename]

When you run the Test query, indeed you get:

There is no data from input '<eventhubinstancename>'. Please make sure the input source has data and then try again.

And a consumer group "preview_data_consumer_group" is created.

It is a pity that we do not see the messages.

Sander van de Velde | MVP 32,726 Reputation points MVP

2024-09-27T15:43:29.1133333+00:00

Well, in my case it's just a handful of messages so there are no extra costs involved.

This number is nothing compared to the very large number of regular telemetry messages I will process using the EventHub.

It would be better if these technical retrieval attempts were hidden for us, the users.
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