Introduction
Modern applications are rarely built as a single monolithic system. Instead, they often consist of multiple services, APIs, databases, message queues, and background workers working together to deliver business functionality.
While this architecture improves scalability and flexibility, it also introduces a significant challenge: understanding how requests flow through the system.
When a user reports a slow response or an unexpected error, developers need visibility into every component involved in processing that request. This is where distributed tracing becomes essential.
.NET Aspire simplifies observability for cloud-native applications by providing built-in integrations for monitoring, telemetry collection, and distributed tracing. Combined with production-ready dashboards, distributed tracing helps teams quickly diagnose performance issues and improve system reliability.
In this article, you'll learn how distributed tracing works, how .NET Aspire supports it, and how to build dashboards that provide meaningful operational insights.
What Is Distributed Tracing?
Distributed tracing is the process of tracking a request as it travels across multiple services and components.
Consider the following workflow:
User Request
|
v
API Gateway
|
v
Order Service
|
v
Payment Service
|
v
Database
Without distributed tracing, it can be difficult to determine:
Which service is slow
Where failures occur
How requests move through the system
Which dependencies affect performance
Distributed tracing provides end-to-end visibility into the request lifecycle.
Why Distributed Tracing Matters
Traditional application logs often provide only isolated information.
For example:
API Request Started
Payment Processed
Database Updated
While useful, these logs do not show how the events are connected.
Distributed tracing adds context by linking operations together.
Benefits include:
Faster troubleshooting
Root cause analysis
Performance optimization
Service dependency visibility
Better production monitoring
For microservice architectures, distributed tracing is often a necessity rather than a luxury.
Understanding Traces, Spans, and Context
Before building dashboards, it is important to understand the core concepts.
Trace
A trace represents the complete journey of a request.
Example:
Place Order Request
Span
A span represents a single operation within a trace.
Example:
Order Service Processing
Payment Validation
Database Query
Context Propagation
Context propagation ensures that tracing information follows requests as they move between services.
This allows monitoring systems to reconstruct the entire request flow.
How .NET Aspire Supports Distributed Tracing
.NET Aspire provides built-in support for observability using OpenTelemetry.
Key capabilities include:
Automatic telemetry collection
Distributed tracing
Metrics collection
Logging integration
Dashboard support
Developers can monitor application behavior without manually implementing complex tracing infrastructure.
Creating an Aspire Application
A typical Aspire solution contains multiple projects.
Example:
AspireAppHost
OrderService
PaymentService
NotificationService
The App Host manages service orchestration and observability across the entire application.
Enabling OpenTelemetry
OpenTelemetry serves as the foundation for distributed tracing.
Configure tracing in your application:
builder.Services.AddOpenTelemetry()
.WithTracing(tracing =>
{
tracing.AddAspNetCoreInstrumentation();
tracing.AddHttpClientInstrumentation();
tracing.AddSqlClientInstrumentation();
});
This configuration captures telemetry from:
ASP.NET Core requests
HTTP calls
SQL Server operations
The resulting traces can be visualized in dashboards.
Instrumenting Custom Operations
Business operations often require custom spans.
Example:
using System.Diagnostics;
var activitySource =
new ActivitySource("OrderProcessing");
Create a custom span:
using var activity =
activitySource.StartActivity(
"ValidateOrder");
activity?.SetTag(
"order.id",
orderId);
This additional metadata improves trace visibility.
Example: Tracking an Order Workflow
Suppose an e-commerce application processes an order.
Workflow:
Order API
|
v
Inventory Service
|
v
Payment Service
|
v
Shipping Service
Each service creates spans that contribute to the overall trace.
Result:
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