Creating a Stateless Service in Azure Service Fabric

Creating a Stateless Service in Service Fabric

In this tutorial, you will learn how to create, deploy, and test a simple Stateless Service inside a Service Fabric application. This is one of the most common types of microservices used when no local data persistence is required.

🌟 What is a Stateless Service?

A Stateless Service does not maintain any client-specific information or state between calls. Every incoming request is processed independently.

• Examples: Web API, Background worker services, Notification senders.
• Scaling is simpler — no synchronization required between instances.

Real-World Analogy:

Think of a public vending machine — each customer operates independently; the machine doesn't remember who used it before.

🛠️ Prerequisites

• Service Fabric SDK installed.
• Local or Azure Service Fabric cluster running.
• Visual Studio 2022 (or higher) installed.

🚀 Step-by-Step Guide: Create and Deploy a Stateless Service

Step 1: Create a New Service Fabric Application

1. Open Visual Studio → File → New → Project.
2. Search for "Service Fabric Application".
3. Choose an appropriate name (e.g., StatelessAppDemo).

Step 2: Add a Stateless Service

1. In the service type selection window, choose: Stateless ASP.NET Core Web API or Stateless Worker Service.
2. Click OK to scaffold your service.

Step 3: Understand the Generated Code

• The main class will inherit from:

  public class YourServiceName : StatelessService
              

• Overridden methods:
  • CreateServiceInstanceListeners: Setup listeners for communication (HTTP, Remoting).
  • RunAsync: Main execution method for your stateless background logic.

Step 4: Modify the Service (Optional)

Update the RunAsync method to implement your custom logic, like sending notifications, polling APIs, etc.

Step 5: Build and Deploy the Application

• Right-click on the solution → Build.
• Right-click the Application Project (.sfproj) → Publish.
• Select Local Cluster or Azure Cluster.
• Click Publish.

Step 6: Verify Deployment

• Open Service Fabric Explorer.
• Expand "Applications" → See your deployed app and service instance.
• Check service health and partition information.

📈 Visual Flow Summary

[Create New SF App] 
    → [Add Stateless Service] 
        → [Customize RunAsync()] 
            → [Build and Publish] 
                → [Monitor in Explorer]
    

💡 Did You Know?

⚡ Common Beginner Mistakes and Solutions

• Problem: Application fails during publishing.
  Solution: Ensure the local cluster is healthy and started before publishing.
• Problem: No HTTP endpoint found.
  Solution: Check if ServiceInstanceListeners are properly configured in your service code.
• Problem: Scaling issues.
  Solution: Stateless services don't need sticky sessions — configure load balancer correctly.

🚨 Best Practices

• Separate stateless services from stateful data logic — keep services truly stateless.
• Implement retry policies for external HTTP calls inside stateless services.

✅ Self-Check Quiz

• What method is overridden to write the background execution logic?
• What are ServiceInstanceListeners used for?
• Can Stateless Services be scaled easily? Why?