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Difficulty: HardImplement Azure Event Hubs Solutions

You are implementing an event processor client in a C# (.NET) application using the `Azure.Messaging.EventHubs.Processor` library. The application consumes telemetry from an Azure Event Hub and uses an Azure Blob Storage container to store checkpoints and partition ownership metadata.

During a deployment, you encounter the following two issues:
1. A secondary management service in the application fails with an HTTP 412 (Precondition Failed) error when attempting to append custom monitoring metadata directly to the active partition ownership lease blobs.
2. The event processor client fails to authenticate with the Storage account when using a User-Assigned Managed Identity, throwing an credential authentication exception.

Which of the following actions should you perform to resolve these issues? (Select TWO)

  1. In the secondary management service, retrieve the active lease ID of the partition ownership blob and include it in the request headers when modifying the blob's metadata.Answer
  2. B
    Perform metadata updates directly on the partition ownership blob without providing a lease ID, as Azure Storage allows concurrent metadata modifications on leased blobs.
  3. Initialize DefaultAzureCredentialOptions with the explicit ClientId of the User-Assigned Managed Identity, and pass these options when creating the DefaultAzureCredential.Answer
  4. D
    Instantiate the credentials using DefaultAzureCredential without parameters, as Azure will automatically discover and utilize the User-Assigned Managed Identity in a multi-identity environment.

Answer

To resolve these issues, you must include the active lease ID in the request headers when modifying the partition ownership blob's metadata, and configure DefaultAzureCredentialOptions with the explicit ClientId of the User-Assigned Managed Identity when instantiating the credential.
The correct options ensure that the application handles active blob leases and configures credentials properly. Modifying a leased blob requires passing the active lease ID to satisfy Azure Storage concurrency constraints. Additionally, configuring the DefaultAzureCredential with the specific Client ID allows the application to successfully authenticate using the designated User-Assigned Managed Identity.

Step-by-Step Solution

1
Address the HTTP 412 error on the partition ownership lease blobs.
Identify that because the EventProcessorClient actively leases these blobs to track ownership, any external service attempting to write to or modify the metadata of these blobs must supply the active lease ID.
Azure Blob Storage enforces write-locks on leased blobs, making the lease ID mandatory for any modifications.
2
Address the authentication failure for the User-Assigned Managed Identity.
Configure the DefaultAzureCredential constructor by passing DefaultAzureCredentialOptions containing the target User-Assigned Managed Identity's Client ID.
Without explicit configuration, the credential defaults to the System-Assigned Managed Identity or fails to distinguish between multiple assigned identities.

Key Concept

Handling active partition leases in Blob Storage checkpointing and authenticating Event Hubs clients using User-Assigned Managed Identities.
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Topics

Implement Azure Event Hubs Solutions