Configuring External Load Balancers with Ingress Controllers

In this lesson, you will learn how to bridge the gap between external web traffic and your internal .NET microservices using Kubernetes Ingress controllers like Nginx or Traefik.

Why Ingress Controllers?

While Kubernetes Services handle internal traffic, they are not designed for sophisticated HTTP/S routing. An Ingress controller acts as a reverse proxy, sitting at the edge of your cluster. It receives external requests, performs SSL/TLS termination, and routes traffic based on hostnames or URL paths to your specific .NET services.

Routing Traffic to .NET

To expose a .NET application, you define an Ingress resource. This manifest tells the controller which host (e.g., api.example.com) should map to your .NET service. Since your .NET app is already configured with Health Check Integration via ASP.NET Core Middleware, the Ingress controller will use these endpoints to ensure traffic only reaches pods that are ready to process requests.

Here is a simplified example of how an Ingress manifest routes traffic to a .NET service:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: dotnet-app-ingress
spec:
  ingressClassName: nginx
  rules:
  - host: api.myapp.com
    http:
      paths:
      - path: /orders
        pathType: Prefix
        backend:
          service:
            name: order-service
            port:
              number: 80

The Workflow

1. The External Load Balancer: Your cloud provider provisions a load balancer that forwards all incoming traffic to the Ingress controller pods.
2. The Ingress Controller: Acting as an intelligent router, the controller inspects the host header or URL path (e.g., /orders) defined in your manifest.
3. Internal Routing: The controller locates the endpoint (the IP address of your .NET pod) and directs the traffic directly to your Kestrel web server.

By offloading concerns like SSL termination and path-based routing to the Ingress controller, your .NET code remains focused on business logic rather than infrastructure concerns. This separation ensures that your application scales predictably while maintaining a clean, professional entry point for external consumers.

Key Takeaway: An Ingress controller functions as the intelligent edge of your cluster, routing external HTTP/S traffic to internal .NET services while handling complex concerns like load balancing and SSL termination at the infrastructure layer.