AZ-204 Develop Azure compute solutions — 100 Questions

Question 1

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.

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Function chaining

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Monitor

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Human interaction

Question 2

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.

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The function uses blob output binding incorrectly.

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

Question 3

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.. Option C is correct because 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.

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Use Key Vault references in App Settings.

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Hardcode the connection string.

Question 4

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.

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Entity trigger

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Activity trigger with retry policy

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Timer trigger

Question 5

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.

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Environment variables in the container group

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Azure Files volume mounted into the container

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ConfigMap in a Kubernetes cluster

Question 6

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.

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Auto-scaling

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Traffic Manager

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Application Insights

Question 7

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.

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emptyDir

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Host path

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Secret volume

Question 8

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.

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App Service Plan

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Premium Plan

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Dedicated Plan

Question 9

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.

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emptyDir volume

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Azure Disk

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ConfigMap

Question 10

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.

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Auto-scaling

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Backup

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Custom domains

Question 11

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

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Event Grid trigger on Consumption plan

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Blob Storage trigger on Premium plan

Question 12

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.

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Store logs in Azure Container Registry

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Use a Docker volume in the container

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Pass log path via an environment variable

Question 13

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.

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HTTP trigger + Consumption plan

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Queue trigger + Consumption plan

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Timer trigger + Consumption plan

Question 14

You are deploying a background processing job that reads messages from an Azure Storage Queue. The job must run on the same compute resources as the main web application and must not require additional deployment or monitoring overhead. Which solution should you use?

Accepted Answer

Add an Azure WebJob to the App Service that hosts the main application.. Option B is correct because Azure WebJobs run in the same App Service plan as the main web application, sharing compute resources without requiring separate deployment or monitoring. A WebJob with a continuous trigger can read from an Azure Storage Queue using the QueueTrigger attribute, meeting the requirement of no additional overhead.

Answer

Deploy an Azure Function with a Queue trigger on the Consumption plan.

Answer

Create a separate Azure Container Instance to run a continuous job.

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Use Azure Logic Apps with a recurrence trigger to poll the queue.

Question 15

You need to deploy a container that runs a simple web server on Azure Container Instances. The container should be accessible via a public IP address. Which property should you set in the container group configuration?

Accepted Answer

ipAddress.type = "Public". To make a container group accessible from the internet via a public IP address, you must set the `ipAddress.type` property to `"Public"`. This instructs Azure Container Instances to assign a public IP and optionally a fully qualified domain name (FQDN) to the container group, allowing inbound traffic from the internet to reach the container's exposed ports.

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osType = "Linux"

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restartPolicy = "Always"

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volumes.mountPath = "/mnt"

Question 16

You are deploying a Docker container to Azure Container Instances (ACI). The container must use GPU resources for machine learning inference. You need to select the appropriate option to provision GPU-enabled containers. What should you do?

Accepted Answer

Deploy the container to a container group with a GPU-enabled SKU (e.g., NV series).. Azure Container Instances supports GPU resources only when you deploy a container group using a GPU-optimized SKU, such as the NV-series (e.g., Standard_NC6s_v3). These SKUs provide NVIDIA Tesla GPUs (e.g., K80, P100, V100) that are directly exposed to the container, enabling hardware-accelerated machine learning inference. You must specify the GPU SKU in the container group's resource requests during deployment, and the container image must include the appropriate NVIDIA CUDA drivers or runtime.

Answer

Mount a GPU volume from the host.

Answer

Use Azure Batch with GPU-enabled pools.

Answer

Enable container GPU support in the Dockerfile.

Question 17

You are deploying a containerized application to Azure Container Instances. The application requires a custom domain name and SSL/TLS termination. You need to configure these features. Which resource should you create alongside the container group?

Accepted Answer

Azure Application Gateway. Azure Application Gateway provides Layer 7 load balancing with SSL/TLS termination and custom domain support. By associating a custom domain with the Application Gateway's frontend IP and uploading an SSL certificate, you can terminate HTTPS connections at the gateway and forward traffic to the container group over HTTP. This meets the requirement without exposing the container group directly.

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Azure Front Door

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Azure Container Registry

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Azure DNS zone

Question 18

You develop an Azure Function app that processes orders. The function must write order status updates to a database. You need to ensure that if the function fails after writing to the database, the order is not lost and can be retried. Which pattern should you implement?

Accepted Answer

Use a Durable Functions orchestration. Option A is correct because Durable Functions orchestrations provide built-in support for reliable execution and automatic retry on failure. By using an orchestration, you can write the order status to the database as an activity function, and if the function fails after the write, the orchestration can replay from the last checkpoint, ensuring the order is not lost and can be retried without duplicating the write.

Answer

Use a retry policy in the function code

Answer

Enable function-level exception handling

Answer

Use an Azure Storage Queue for the function input

Question 19

You are building a serverless image-processing solution using Azure Functions. The function must automatically run whenever a new image is uploaded to a blob container and must scale out to handle high upload volumes. Which trigger and hosting plan should you use?

Accepted Answer

Blob trigger with Consumption plan. The Blob trigger is designed to automatically execute a function when a blob is created or updated in Azure Blob Storage, making it the correct choice for an image-processing solution that must run on new uploads. The Consumption plan provides automatic scaling to handle high upload volumes by allocating resources on demand, which aligns with the serverless, event-driven requirement.

Answer

Timer trigger with Consumption plan

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HTTP trigger with Premium plan

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Queue trigger with App Service plan

Question 20

You deploy a container to Azure Container Instances (ACI). The container runs a background job that should automatically restart only if it exits with a non-zero exit code (i.e., crashes). You want to minimize costs. Which restart policy should you configure?

Accepted Answer

Set restart policy to OnFailure and use a single container group. The OnFailure restart policy restarts the container only when it exits with a non-zero exit code, which matches the requirement to restart only on crashes. This policy minimizes costs because the container does not run continuously when it exits successfully, unlike the Always policy. Using a single container group is the simplest and most cost-effective deployment for a single background job.

Answer

Set restart policy to Always and use a private container registry

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Set restart policy to Never and use a public container registry

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Set restart policy to OnFailure and deploy in a virtual network