AZ-204 Practice Test 9 — 10 Questions

Question 1

The mobile app team needs to send push notifications to 10 million devices running both iOS and Android. On iOS, notifications go through Apple Push Notification service (APNs); on Android, through Firebase Cloud Messaging (FCM). The team wants a single Azure service that abstracts platform differences and scales without managing separate APNs and FCM integrations per platform. Which service should they use?

Accepted Answer

Azure Notification Hubs with APNs and FCM credentials configured in the hub namespace. Azure Notification Hubs is the correct choice because it is a fully managed push notification service designed to abstract platform-specific notification systems like APNs (iOS) and FCM (Android). By configuring the APNs and FCM credentials in the hub namespace, the team can send a single notification that is automatically routed to the correct platform service, scaling to millions of devices without managing separate integrations.

Answer

Azure Service Bus with topics — one subscription per platform, each subscription delivering to APNs or FCM

Answer

Azure Event Grid with a custom endpoint handler per platform that calls APNs or FCM directly

Answer

Azure Communication Services email with HTML-formatted alerts sent to device email addresses

Question 2

A high-traffic API sends approximately 80,000 telemetry events per second to Application Insights. Monthly ingestion costs are too high. The team wants to reduce data volume by roughly 80 percent while still seeing representative samples of all request types. What should the developer configure?

Accepted Answer

Enable adaptive sampling in the Application Insights SDK and set a target events-per-second limit. Adaptive sampling in the Application Insights SDK automatically adjusts the volume of telemetry sent to the service, targeting a specified rate of events per second. By setting a target that reduces the original 80,000 events/sec to roughly 20%, the SDK will intelligently sample all request types proportionally, preserving representative data while cutting costs.

Answer

Configure ingestion sampling in the Azure portal to retain 20 percent of incoming telemetry

Answer

Increase the TelemetryClient flush interval from 30 seconds to 5 minutes to batch events

Answer

Filter all events with HTTP status code 200 from the telemetry pipeline before sending

Question 3

An e-commerce platform writes orders to a Cosmos DB container. A downstream inventory service must process every new or updated order exactly once, even if the inventory service restarts mid-batch. The solution must scale horizontally when order volume increases. What is the recommended design?

Accepted Answer

Use the change feed processor library with a dedicated lease container; each worker instance claims partition leases and commits checkpoints after processing each batch. The change feed processor library with a dedicated lease container is the recommended design because it provides exactly-once processing semantics through checkpointing, automatic partition lease management for horizontal scaling, and resilience to worker restarts by resuming from the last committed checkpoint. This pattern is purpose-built for Cosmos DB change feed consumption in distributed systems.

Answer

Poll the Cosmos DB container every 30 seconds using a _ts timestamp filter to find recently modified documents

Answer

Subscribe to Azure Event Grid Cosmos DB events and process them in an Azure Function

Answer

Enable Cosmos DB analytical store and run batch queries from an Azure Synapse Spark pool every hour

Question 4

A Windows desktop application uses standard .NET file system calls such as File.ReadAllText and Directory.GetFiles. The team wants to move the file storage to Azure. The application code must not be rewritten. Which Azure storage service supports this requirement?

Accepted Answer

Azure Files with an SMB share mounted as a drive letter on the Windows machine. Azure Files with an SMB share mounted as a drive letter on the Windows machine allows the existing .NET application to use standard file system calls like File.ReadAllText and Directory.GetFiles without any code changes. This is because the mounted SMB share presents itself as a local drive, and the .NET runtime interacts with it through the standard Windows file system API, which internally uses the SMB protocol (CIFS) to communicate with Azure Files. No SDK or API rewrite is required.

Answer

Azure Blob Storage with the Azure Storage SDK replacing all file system calls

Answer

Azure Queue Storage for staging files between producer and consumer processes

Answer

Azure Table Storage with the file content stored as base64-encoded entity properties

Question 5

The team needs to receive an email when an App Service's HTTP 5xx error rate exceeds 5 percent for more than five consecutive minutes. No custom code should be written. What combination of Azure Monitor features implements this requirement?

Accepted Answer

Create a metric alert on the Http5xxErrors metric with a 5-percent threshold, a 5-minute evaluation window, and an action group that sends email. Option A is correct because Azure Monitor metric alerts can directly evaluate the Http5xxErrors metric over a specified time window (e.g., 5 minutes) and trigger an action group when the threshold (5%) is breached. This requires no custom code and uses the native metric alert pipeline, which polls the metric every minute and aggregates over the evaluation window to detect sustained violations.

Answer

Create a log alert that queries the App Service diagnostic log table every 5 minutes and emails the team if the 5xx count exceeds a threshold

Answer

Enable Application Insights availability tests and configure an alert on test failure rate

Answer

Configure a diagnostic setting to stream logs to Azure Storage, then write a Function that reads the storage file and sends email when errors are found

Question 6

Three microservices collaborate on a single user transaction: an App Service API, an Azure Function that processes a Service Bus message, and a downstream storage service. Traces appear separately in Application Insights with no parent-child relationship. What is needed to correlate all three into a single end-to-end trace?

Accepted Answer

Install the Application Insights SDK on all three services and ensure W3C Trace Context header propagation is enabled for both HTTP calls and Service Bus messages. Option A is correct because distributed tracing across HTTP and asynchronous messaging requires the Application Insights SDK on each service and propagation of the W3C Trace-Context standard (traceparent and tracestate headers). This ensures that the App Service API, Azure Function, and downstream storage service share a single trace ID, enabling Application Insights to correlate all telemetry into one end-to-end transaction view.

Answer

Use the same Application Insights instrumentation key for all three services — no additional configuration is needed

Answer

Add a custom x-correlation-id header in each service and log it with TelemetryClient.TrackEvent

Answer

Enable Azure Monitor cross-resource queries and write a KQL join across all three services' logs

Question 7

After deploying a new version to the staging slot and swapping to production, users report a 60-second spike in 503 errors. The application takes 45 seconds to initialize its connection pools and caches before it can serve traffic. What is the root cause, and what should the developer configure to prevent this?

Accepted Answer

Configure Application Initialization in the App Service settings so the swap waits for the warm-up path to return 200 before redirecting production traffic. The root cause is that the swap operation immediately redirects production traffic to the new slot before the application has finished its 45-second initialization (connection pools, caches). Application Initialization (warm-up) in Azure App Service can be configured to send a request to a specified path and wait for a 200 response before completing the swap, ensuring the app is ready to serve traffic. This eliminates the 503 errors by preventing the swap from routing users to an uninitialized instance.

Answer

Roll back the slot swap and investigate the new version for bugs that only appear in production

Answer

Increase the App Service health check grace period so the load balancer waits longer after the swap

Answer

Disable Always On for the staging slot so the slot starts fresh on every swap

Question 8

Users of a web application hosted on App Service are randomly signed out when the app is scaled out to three instances. Investigation shows that session data stored in in-process memory is not available when subsequent requests hit a different instance. What is the recommended solution?

Accepted Answer

Store session data in Azure Cache for Redis and configure all App Service instances to connect to the same Redis endpoint. When an App Service scales out to multiple instances, in-process session state is stored locally on each instance and is not shared. Azure Cache for Redis provides a centralized, in-memory data store that all instances can access, ensuring session data is available regardless of which instance handles a request. This is the recommended pattern for distributed session state in Azure.

Answer

Enable ARR affinity (sticky sessions) on the App Service to route each user's requests to the same instance

Answer

Write session data to Azure Blob Storage as a JSON file keyed by session ID on every request

Answer

Store session state in a Cosmos DB container with a TTL equal to the session timeout

Question 9

A booking backend uses Azure Functions with HTTP triggers. The developer wants to reject unauthenticated calls before function code executes. Which feature should be configured?

Accepted Answer

App Service Authentication / Easy Auth with Microsoft Entra ID. App Service Authentication (Easy Auth) with Microsoft Entra ID allows the developer to reject unauthenticated calls before the function code executes by configuring the 'Action to take when request is not authenticated' to 'Log in with Microsoft Entra ID' or 'Return HTTP 401 Unauthorized'. This is enforced at the App Service platform layer, meaning the function trigger code never runs for unauthenticated requests, which is exactly the requirement.

Answer

Application Insights sampling

Answer

Deployment slots

Answer

Function timeout

Question 10

An API receives JWT access tokens from Microsoft Entra ID. Which two token properties should the API validate before accepting a request? The team wants the control to be enforceable during normal operations.

Accepted Answer

Issuer and signature are valid for the trusted tenant. Option A is correct because validating the issuer and signature ensures the JWT was issued by the trusted Microsoft Entra ID tenant and has not been tampered with. The issuer claim (iss) must match the tenant-specific issuer URL (e.g., https://login.microsoftonline.com/{tenant-id}/v2.0), and the signature must be verified using the public keys from the OpenID Connect metadata endpoint. This is a fundamental security requirement for any API that accepts tokens from Entra ID.

Answer

The user's display name is present

Answer

The token was sent in a query string