Inspect distributed tracing by using Application Insights

Application Insights is part of Azure Monitor and Microsoft’s application performance management (APM) service. It provides real-time telemetry, automatic anomaly detection, powerful analytics, and seamless integration with Azure services and DevOps toolchains. In this guide, you’ll learn how to enable, configure, and explore distributed tracing for your .NET web app using Application Insights.

Table of Contents

1. Key Features
2. Enable Application Insights in Azure Portal
3. Add the Application Insights SDK
4. Configure the Instrumentation Key
5. Explore Telemetry in Application Insights
   • Overview Dashboard
   • Live Metrics Stream
   • Application Map
   • Performance
   • Failures
   • Availability
6. Configure Alerts
7. Diagnostic Settings & Log Analytics
8. References

Key Features

Enable Application Insights in Azure Portal

1. In the Azure Portal, create or select your Web App (e.g., KodeKloud Support).
2. Under Deployment > Networking, configure required networking options.
3. Navigate to Monitor and Secure, toggle Application Insights to Yes.
4. Choose an existing resource or create a new one for KodeKloud Support.
5. (Optional) Enable Defender for additional security monitoring.
6. Click Review + create to finalize.

Add the Application Insights SDK

Open your project in Visual Studio and update your front‐end page if needed. For example, your Index.cshtml might look like this:

@page
@model IndexModel
@{
    ViewData["Title"] = "Home page";
}
<div class="hero-image" style="background-image: url('/img/frontpage.jpg'); background-size: cover; background-position: center;">
    <h1 class="display-4 text-white">Welcome to Kode Kloud</h1>
</div>
<div class="container mt-4">
    <div class="row">
        <div class="col-md-8 offset-md-2 text-center">
            <h2>Expert Tech Support at Your Service</h2>
            <p class="lead">
                At Kode Kloud, our dedicated tech support team is committed to providing you with exceptional service. With our extensive knowledge and passion for problem-solving, we're here to ensure your team runs smoothly, allowing you to focus on what matters most – your success.
            </p>
        </div>
    </div>
</div>

Then install the Application Insights SDK package:

PM> Install-Package Microsoft.ApplicationInsights.AspNetCore

Configure the Instrumentation Key

1. In the Azure Portal, go to Monitor > Application Insights > KodeKloud Support.
2. Under Instrument your application, select .NET and the Recommended Basic level.
3. Enable the Profiler and click Apply.

4. Copy the Instrumentation Key, then add it to appsettings.json:

{
  "ApplicationInsights": {
    "InstrumentationKey": "YOUR_INSTRUMENTATION_KEY"
  }
}

5. Update your application startup (Program.cs or Startup.cs):

using Microsoft.ApplicationInsights.Extensibility;

var builder = WebApplication.CreateBuilder(args);

// Add Application Insights telemetry
builder.Services.AddApplicationInsightsTelemetry();

var app = builder.Build();
app.Run();

Build and run locally to verify telemetry, then deploy through your CI/CD pipeline.

Explore Telemetry in Application Insights

After deployment, navigate to Monitor > Application Insights > KodeKloud Support.

Overview Dashboard

The Overview dashboard presents high-level metrics:

• Failed requests
• Server response time
• Server requests
• Availability

Live Metrics Stream

1. Go to Live Metrics and reset the view.
2. Generate traffic to monitor request rate, duration, CPU usage, and memory in real time.

Live metrics are ideal for high-load scenarios and can be displayed on a team dashboard.

Application Map

The Application Map visualizes components, dependencies, instance counts, and response times. It also highlights top failures and slowest requests.

Performance

Review operations by response time to identify slow dependencies or endpoints.

Failures

Inspect error types and counts. In this demo, we intentionally generated 4,800 HTTP 404 errors.

Availability

Track uptime and response trends over time to assess reliability.

Configure Alerts

Define alert rules to get notified when metrics cross thresholds.

1. In the portal, choose Alerts > New alert rule.
2. Select the target resource and signal type (e.g., Failed requests).
3. Set the condition logic and threshold.

4. On Actions, choose or create an action group to send email, SMS, or webhook notifications.

Tip: Pin custom metric charts to your dashboard for quick visibility.

Diagnostic Settings & Log Analytics

1. Under Diagnostic settings, configure streaming export of logs and metrics to storage, Event Hubs, or Log Analytics.

2. Use Log Analytics to run Kusto queries on your telemetry and logs for advanced diagnostics.

References

• Azure Monitor Application Insights
• Kusto Query Language (KQL)
• Secure your secrets with Azure Key Vault