Application Insights for apps in Azure - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

How does Application Insights collect telemetry data?

Application Insights gathers data from your app to monitor its performance and usage. Which method below correctly describes how it collects telemetry?

A By scanning the app's source code for errors without running it.

B By manually exporting logs from the app and uploading them to Azure.

C By embedding a monitoring SDK in the app that sends telemetry data to Azure.

D By using Azure Storage to store app files and analyzing them offline.

💡 Hint

Think about how real-time monitoring tools work inside an app.

Application Insights uses an SDK embedded in your app to send telemetry data automatically to Azure for monitoring.

❓ Architecture

intermediate

Which Azure resource is required to enable Application Insights for a web app?

You want to monitor your Azure Web App using Application Insights. Which resource must you create or link to enable this?

A An Azure Virtual Machine to run the monitoring agent.

B An Azure SQL Database to log application errors.

C An Azure Storage account to store telemetry data.

D An Application Insights resource in the same Azure subscription.

💡 Hint

Consider what resource directly supports Application Insights data collection.

Application Insights requires a dedicated resource in Azure to receive and analyze telemetry data from your app.

❓ security

advanced

What is the best practice to secure Application Insights instrumentation key in your app?

To protect your Application Insights data, how should you handle the instrumentation key in your application?

A Hardcode the instrumentation key directly in the app's source code for easy access.

B Store the instrumentation key in environment variables or secure configuration stores, not in source code.

C Share the instrumentation key publicly to allow all team members to monitor the app.

D Embed the instrumentation key in client-side JavaScript to track user behavior.

💡 Hint

Think about how to keep sensitive keys safe from unauthorized access.

Storing keys in environment variables or secure stores prevents accidental exposure and improves security.

❓ Configuration

advanced

What happens if you disable sampling in Application Insights for a high-traffic app?

Sampling reduces the amount of telemetry sent to Application Insights. What is the effect of disabling sampling on a busy app?

A Telemetry volume increases, possibly causing higher costs and slower processing.

B Telemetry volume decreases, improving performance and reducing costs.

C The app stops sending any telemetry data to Application Insights.

D Application Insights automatically filters out errors but keeps all traces.

💡 Hint

Consider what happens when all telemetry is sent without filtering.

Disabling sampling means all telemetry is sent, increasing data volume, costs, and processing time.

🧠 Conceptual

expert

Which query correctly returns the count of failed requests in Application Insights logs?

You want to find how many requests failed in your app using Application Insights Analytics. Which Kusto query returns the count of failed requests?

Azure

requests | where success == false | summarize count()

A requests | where success == false | summarize count()

B requests | where success = false | summarize count()

C requests | filter success == false | count()

D requests | where success == false | count

💡 Hint

Remember the correct syntax for filtering and counting in Kusto Query Language.

The correct syntax uses 'where' to filter and 'summarize count()' to count rows.

Practice

1. What is the main purpose of Azure Application Insights?

easy

A. To monitor the health and usage of applications

B. To create virtual machines in Azure

C. To store large amounts of data

D. To manage user identities and access

Solution

1. Step 1: Understand Application Insights role

   Application Insights is designed to monitor apps by collecting data about their performance and usage.

2. Step 2: Compare with other Azure services

   Other options like virtual machines, data storage, or identity management are handled by different Azure services.

3. Final Answer:

   To monitor the health and usage of applications -> Option A

4. Quick Check:

   Monitoring apps = To monitor the health and usage of applications [OK]

Hint: Think monitoring and diagnostics for apps [OK]

Common Mistakes:

• Confusing Application Insights with storage services
• Mixing it up with Azure Active Directory
• Assuming it creates or manages infrastructure

2. Which of the following is the correct way to enable Application Insights in an Azure Web App?

easy

A. Create a virtual machine and install Application Insights manually

B. Add Application Insights SDK and configure instrumentation key

C. Enable Azure Monitor logs only

D. Use Azure Blob Storage to store telemetry data

Solution

1. Step 1: Identify how to enable Application Insights

   Enabling Application Insights requires adding its SDK to the app and setting the instrumentation key for telemetry.

2. Step 2: Eliminate incorrect options

   Creating VMs or using Blob Storage does not enable Application Insights. Azure Monitor logs are related but separate.

3. Final Answer:

   Add Application Insights SDK and configure instrumentation key -> Option B

4. Quick Check:

   SDK + instrumentation key = Add Application Insights SDK and configure instrumentation key [OK]

Hint: SDK plus key enables monitoring [OK]

Common Mistakes:

• Thinking Application Insights runs on VMs only
• Confusing Azure Monitor logs with Application Insights
• Using storage services for telemetry data

3. Given this snippet in an Azure Function app:

var telemetryClient = new TelemetryClient();
telemetryClient.TrackEvent("OrderPlaced");

What will Application Insights record?

medium

A. An error log with message 'OrderPlaced'

B. A performance metric for function execution time

C. An event named 'OrderPlaced' in the telemetry data

D. No data because TelemetryClient is not initialized

Solution

1. Step 1: Understand TrackEvent method

   TrackEvent sends a custom event named as the string argument to Application Insights.

2. Step 2: Check the code behavior

   The code creates a TelemetryClient and tracks an event called 'OrderPlaced', so this event will be recorded.

3. Final Answer:

   An event named 'OrderPlaced' in the telemetry data -> Option C

4. Quick Check:

   TrackEvent sends event = An event named 'OrderPlaced' in the telemetry data [OK]

Hint: TrackEvent logs custom events [OK]

Common Mistakes:

• Assuming TrackEvent logs errors
• Thinking it measures performance automatically
• Believing TelemetryClient needs extra setup to send events

4. You added Application Insights to your app but see no telemetry data in the Azure portal. What is the most likely cause?

medium

A. Application Insights service is not available in your region

B. Azure subscription is expired

C. You need to restart the Azure portal

D. Instrumentation key is missing or incorrect in app configuration

Solution

1. Step 1: Check telemetry data flow requirements

   Telemetry requires the correct instrumentation key configured in the app to send data to Application Insights.

2. Step 2: Evaluate other options

   Subscription expiry or service region issues would cause broader failures, and restarting the portal does not affect telemetry data.

3. Final Answer:

   Instrumentation key is missing or incorrect in app configuration -> Option D

4. Quick Check:

   Missing key blocks telemetry = Instrumentation key is missing or incorrect in app configuration [OK]

Hint: Check instrumentation key first [OK]

Common Mistakes:

• Restarting portal expecting data to appear
• Assuming regional availability blocks telemetry silently
• Ignoring app configuration settings

5. You want to monitor a multi-service app with Application Insights and correlate requests across services. What should you do?

hard

A. Enable distributed tracing and use the same Application Insights resource for all services

B. Create separate Application Insights resources for each service without linking

C. Use Azure Monitor logs only without Application Insights

D. Send telemetry data manually to a storage account

Solution

1. Step 1: Understand distributed tracing in Application Insights

   Distributed tracing allows tracking requests across multiple services by sharing context and using the same Application Insights resource.

2. Step 2: Compare options for multi-service monitoring

   Using separate resources without linking breaks correlation. Azure Monitor logs alone do not provide this tracing. Manual telemetry to storage lacks correlation features.

3. Final Answer:

   Enable distributed tracing and use the same Application Insights resource for all services -> Option A

4. Quick Check:

   Distributed tracing + shared resource = Enable distributed tracing and use the same Application Insights resource for all services [OK]

Hint: Use distributed tracing with shared resource [OK]

Common Mistakes:

• Splitting telemetry into unlinked resources
• Ignoring distributed tracing setup
• Relying only on logs without correlation