AZ-204 Develop Azure compute solutions Practice Test 3 — 15 Questions

Question 1

You are designing a serverless architecture using Azure Functions for a data processing pipeline. The pipeline must process messages from an Azure Service Bus queue. Each message can take up to 5 minutes to process. You need to ensure that if a function fails, the message is not lost and is retried after a delay. What should you configure?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Configure the Service Bus queue to dead-letter messages after a specified number of delivery attempts.. The original explanation correctly describes the full mechanism involving PeekLock mode, LockDuration (set to at least 5 minutes), MaxDeliveryCount, and dead-lettering. However, option D itself only covers the dead-lettering aspect (implying MaxDeliveryCount) and does not explicitly include the necessary LockDuration configuration, which is a critical part of the solution for the specified requirements.

Answer

Use the PeekLock message receive mode and manually complete the message only after successful processing.

Answer

Use Durable Functions with a retry policy.

Answer

Set the Azure Functions retry policy in the host.json file.

Question 2

You are developing an Azure Functions app that processes orders. Each order must be processed exactly once. The function is triggered by an Azure Event Hubs event. You need to ensure that if the function fails during processing, the event is not lost and is retried. Which THREE actions should you take?

Accepted Answer

Configure a dead-letter queue for events that exceed retry attempts.. To ensure each order is processed exactly once and not lost even if the function fails, three key actions are required:

1.  **Configure a dead-letter queue (DLQ) for events that exceed retry attempts (Option B):** This ensures that events which cannot be processed successfully after exhausting all retries are not lost. They are stored separately for later inspection or reprocessing, preventing data loss and supporting an 'at-least-once' delivery guarantee, which is a prerequisite for 'effectively once' processing.
2.  **Implement checkpointing after successful processing (Option D):** Checkpointing is crucial for Event Hubs consumers to track their progress on a partition. By recording the offset of the last successfully processed event, the function ensures that if it fails and restarts, it will resume processing from the last known good point. This prevents reprocessing events that were already successfully handled (contributing to 'effectively once' processing) and ensures no events are missed.
3.  **Use the default checkpoint store in Azure Storage (Option E):** For checkpointing to be persistent across function restarts and scale-out operations, a reliable storage mechanism is needed. Azure Blob Storage is the standard and default checkpoint store used by the Event Hubs SDK and Azure Functions Event Hubs trigger. This action provides the necessary infrastructure for checkpointing to function correctly.

Answer

Increase the batch size to process more events per invocation.

Answer

Disable checkpointing to avoid overhead.

Question 3

You are implementing an Azure Durable Functions application that processes orders. The function must call three external APIs (payment gateway, inventory system, and shipping calculator) in parallel, then aggregate the results once all three have completed. Which Durable Functions pattern should you use?

Accepted Answer

Fan-out/Fan-in. The Fan-out/Fan-in pattern is designed exactly for this scenario: it triggers multiple function tasks in parallel (fan-out) and then aggregates their results once all complete (fan-in). In Durable Functions, this is implemented using `CallActivityAsync` in a loop with `Task.WhenAll` to wait for all parallel activities to finish, allowing the orchestrator to collect and process the combined results.

Answer

Function chaining

Answer

Monitor

Answer

Human interaction

Question 4

A company uses Azure Functions with a consumption plan. The function processes messages from a queue. During peak hours, the function takes longer to execute, and some messages are processed twice. What is the most likely cause?

Accepted Answer

The queue message visibility timeout is shorter than the function processing time.. In Azure Functions with a consumption plan, the queue message visibility timeout determines how long a message is invisible to other consumers after being dequeued. If the function's processing time exceeds this visibility timeout, the message becomes visible again and can be picked up by another function instance, leading to duplicate processing. This is the most likely cause of messages being processed twice during peak hours when execution times increase.

Answer

The function timeout is set too low.

Answer

The function uses blob output binding incorrectly.

Answer

The function app is using a premium plan instead of consumption.

Question 5

You are deploying a Node.js application to Azure Web Apps for Containers. The application needs to read configuration settings from Azure App Configuration. What is the recommended method to securely connect the app to the configuration store?

Accepted Answer

Use managed identity.. Using a managed identity allows the Node.js application running in Azure Web Apps for Containers to authenticate to Azure App Configuration without storing any secrets. Managed identities provide an automatically managed service principal in Azure AD, enabling secure, code-free access to the configuration store via Azure AD authentication, which is the recommended approach for production workloads.

Answer

Store connection string in environment variables.

Answer

Use Key Vault references in App Settings.

Answer

Hardcode the connection string.

Question 6

You are implementing an order processing system using Azure Durable Functions. The function must send notifications to multiple channels (email, SMS, push) in parallel and wait for all to complete before sending a confirmation. Which Durable Functions feature should you utilize?

Accepted Answer

Orchestration trigger with fan-out/fan-in pattern. The fan-out/fan-in pattern in Durable Functions allows you to invoke multiple activity functions in parallel (fan-out) and then wait for all of them to complete (fan-in) using `Task.WhenAll`. This is exactly what is needed to send notifications to email, SMS, and push simultaneously and then proceed only after all have finished, making option A correct.

Answer

Entity trigger

Answer

Activity trigger with retry policy

Answer

Timer trigger

Question 7

You are deploying a sensitive configuration to Azure Container Instances. The configuration must be encrypted at rest and not visible in the container logs. What should you use?

Accepted Answer

Azure Key Vault with managed identity and secret volumes. Azure Key Vault with managed identity and secret volumes is the correct choice because it allows you to mount secrets as files into the container without exposing them in environment variables or logs. The secrets are encrypted at rest in Key Vault and are only accessible via a managed identity assigned to the container group, ensuring the configuration remains secure and invisible in container logs.

Answer

Environment variables in the container group

Answer

Azure Files volume mounted into the container

Answer

ConfigMap in a Kubernetes cluster

Question 8

A company deploys a web application to Azure App Service. They want to deploy a new version of the app with zero downtime and the ability to quickly roll back if needed. Which deployment feature should they use?

Accepted Answer

Deployment slots. Deployment slots are separate, live environments within Azure App Service that allow you to stage a new version of your app, perform validation, and then swap it into production with zero downtime. The swap operation ensures all traffic is redirected instantly, and if issues arise, you can immediately swap back to the previous slot for a quick rollback.

Answer

Auto-scaling

Answer

Traffic Manager

Answer

Application Insights

Question 9

A company deploys a stateful application as a container in Azure Container Instances (ACI). They need persistent storage that can be shared across multiple container instances and retain data after container restarts. Which volume mount should they use?

Accepted Answer

Azure Files share. Azure Files shares provide fully managed SMB file shares in the cloud that can be mounted as volumes in Azure Container Instances. This allows multiple container instances to read and write to the same persistent storage concurrently, and data persists independently of container lifecycles, surviving restarts or deletions. The scenario requires shared, persistent storage across instances, which Azure Files uniquely supports among the given options.

Answer

emptyDir

Answer

Host path

Answer

Secret volume

Question 10

A company deploys an Azure Function app that processes orders. The function needs to scale out automatically when the queue length grows and be billed only for execution time. Which hosting plan should you use?

Accepted Answer

Consumption Plan. The Consumption Plan is correct because it automatically scales out the function app based on the length of the Azure Storage queue trigger, and you are billed only for the execution time (per-second billing) and resources consumed. This plan is ideal for event-driven workloads like order processing, where scaling is demand-driven and idle time incurs no cost.

Answer

App Service Plan

Answer

Premium Plan

Answer

Dedicated Plan

Question 11

You deploy a containerized application on Azure Container Instances (ACI). The application writes data that must persist across container restarts and be accessible from multiple instances. Which volume mount should you configure?

Accepted Answer

Azure Files share. Azure Files shares provide a fully managed SMB file share in the cloud that can be mounted as a volume in Azure Container Instances. This allows data written by the container to persist across restarts and be accessed concurrently by multiple container instances, meeting the requirements for durability and shared access.

Answer

emptyDir volume

Answer

Azure Disk

Answer

ConfigMap

Question 12

You deploy a web application to Azure App Service. You need to deploy a new version of the application without downtime and have the ability to test the new version before switching traffic. Which feature should you use?

Accepted Answer

Deployment slots. Deployment slots are live, independently running app versions in Azure App Service that allow you to deploy a new build to a staging slot, validate it with zero impact on production, and then swap it into production with instant traffic redirection. This swap operation is atomic and warm-up aware, ensuring no downtime during the transition.

Answer

Auto-scaling

Answer

Backup

Answer

Custom domains

Question 13

You develop an Azure Functions app that processes images triggered by blob uploads. You need to ensure the function can process images in parallel and handle high upload volumes without missing events. Which trigger and plan combination is recommended?

Accepted Answer

Event Grid trigger on Premium plan. The Event Grid trigger on a Premium plan is recommended because Event Grid provides reliable, high-throughput event delivery with built-in retry and dead-lettering, ensuring no blob upload events are missed. The Premium plan offers dedicated instances and VNET connectivity, which avoids cold starts and allows parallel processing of multiple images concurrently, unlike the Consumption plan which has scaling limitations and potential for event loss under high volume.

Answer

Blob Storage trigger on Consumption plan

Answer

Event Grid trigger on Consumption plan

Answer

Blob Storage trigger on Premium plan

Question 14

You deploy a containerized application to Azure Container Instances (ACI). The application writes logs that must persist across container restarts and be accessible from a file system. The solution must minimize cost and complexity. Which configuration should you use?

Accepted Answer

Mount an Azure Files share as a volume. Mounting an Azure Files share as a volume in Azure Container Instances provides persistent, shared file storage that survives container restarts and is accessible via the container's file system. This approach minimizes cost by using standard Azure Files storage (pay only for consumed capacity) and complexity by leveraging ACI's native volume mount support without requiring additional orchestration or stateful infrastructure.

Answer

Store logs in Azure Container Registry

Answer

Use a Docker volume in the container

Answer

Pass log path via an environment variable

Question 15

You develop a serverless application using Azure Functions. The function must process images uploaded to a blob container. You need to ensure the function runs only when a new blob is created, and that it scales out automatically for high upload volumes. Which trigger and hosting plan combination should you use?

Accepted Answer

Blob trigger + Consumption plan. A Blob trigger is designed to run a function when a blob is created or updated in Azure Blob Storage, which directly matches the requirement to process images only when a new blob is uploaded. The Consumption plan provides automatic scaling based on demand, handling high upload volumes by dynamically allocating resources without manual intervention. This combination ensures event-driven execution and cost-effective scaling.

Answer

HTTP trigger + Consumption plan

Answer

Queue trigger + Consumption plan

Answer

Timer trigger + Consumption plan