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Troubleshoot checkpoint store issues

  • Artikkeli

This article discusses issues with using Blob Storage as a checkpoint store.

Issues with using Blob Storage as a checkpoint store

You may see issues when using a blob storage account as a checkpoint store that are related to delays in processing, or failures to create checkpoints when using the SDK, etc.

Follow these recommendations when using Azure Blob Storage as a checkpoint store:

  • Use a separate container for each consumer group. You can use the same storage account, but use one container per each group.
  • Don't use the container for anything else, and don't use the storage account for anything else.
  • Storage account should be in the same region as the deployed application is located in. If the application is on-premises, try to choose the closest region possible.

On the Storage account page in the Azure portal, in the Blob service section, ensure that the following settings are disabled.

  • Hierarchical namespace
  • Blob soft delete
  • Versioning

Using Blob Storage checkpoint store on Azure Stack Hub

If you're using Azure Blob Storage as the checkpoint store in an environment that supports a different version of Storage Blob SDK than the ones that are typically available on Azure, you need to use code to change the Storage service API version to the specific version supported by that environment. For example, if you're running Event Hubs on an Azure Stack Hub version 2002, the highest available version for the Storage service is version 2017-11-09. In this case, you need to use code to target the Storage service API version to 2017-11-09. For an example of how to target a specific Storage API version, see these samples on GitHub:

If you run Event Hubs receiver that uses Blob Storage as the checkpoint store without targeting the version that Azure Stack Hub supports, you receive the following error message:

The value for one of the HTTP headers is not in the correct format

Sample error message in Python

For Python, an error of azure.core.exceptions.HttpResponseError is passed to the error handler on_error(partition_context, error) of EventHubConsumerClient.receive(). But, the method receive() doesn't raise an exception. print(error) prints the following exception information:

The value for one of the HTTP headers is not in the correct format.

RequestId:f048aee8-a90c-08ba-4ce1-e69dba759297
Time:2020-03-17T22:04:13.3559296Z
ErrorCode:InvalidHeaderValue
Error:None
HeaderName:x-ms-version
HeaderValue:2019-07-07

The logger logs two warnings like the following ones:

WARNING:azure.eventhub.extensions.checkpointstoreblobaio._blobstoragecsaio: 
An exception occurred during list_ownership for namespace '<namespace-name>.eventhub.<region>.azurestack.corp.microsoft.com' eventhub 'python-eh-test' consumer group '$Default'. 

Exception is HttpResponseError('The value for one of the HTTP headers is not in the correct format.\nRequestId:f048aee8-a90c-08ba-4ce1-e69dba759297\nTime:2020-03-17T22:04:13.3559296Z\nErrorCode:InvalidHeaderValue\nError:None\nHeaderName:x-ms-version\nHeaderValue:2019-07-07')

WARNING:azure.eventhub.aio._eventprocessor.event_processor:EventProcessor instance '26d84102-45b2-48a9-b7f4-da8916f68214' of eventhub 'python-eh-test' consumer group '$Default'. An error occurred while load-balancing and claiming ownership. 

The exception is HttpResponseError('The value for one of the HTTP headers is not in the correct format.\nRequestId:f048aee8-a90c-08ba-4ce1-e69dba759297\nTime:2020-03-17T22:04:13.3559296Z\nErrorCode:InvalidHeaderValue\nError:None\nHeaderName:x-ms-version\nHeaderValue:2019-07-07'). Retrying after 71.45254944090853 seconds

Next steps

See the following article learn about partitioning and checkpointing: Balance partition load across multiple instances of your application