Introduction:

In Kubernetes, Ingress is an API object that provides HTTP and HTTPS routing to services based on rules. It acts as a layer on top of services to expose them externally and manage external access to different parts of your application. In this guide, we’ll explore what Ingress is, why it’s important, and how to define and use it effectively.

1. What is Kubernetes Ingress?

Ingress is a Kubernetes resource that allows you to define how external traffic should be processed and routed to services within your cluster. It provides a way to manage external access, load balancing, SSL termination, and URL-based routing.

2. Why Use Ingress?

• Path-Based Routing: Ingress allows you to define rules based on URL paths, directing traffic to different services based on the requested path.
• SSL/TLS Termination: You can configure Ingress to handle SSL/TLS termination, offloading the encryption/decryption process from your backend services.
• Load Balancing: Ingress can distribute traffic among multiple backend services, providing load balancing for your application.

3. Creating a Basic Ingress Resource

Here’s an example of a simple Ingress YAML file:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
spec:
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /app
        pathType: Prefix
        backend:
          service:
            name: app-service
            port:
              number: 80

Explanation:

• host: The domain for which the Ingress rules apply.
• paths: Define path-based routing rules.
• backend: Specifies the backend service to which traffic should be directed.

Apply this configuration using:

kubectl apply -f ingress.yaml

4. Accessing Services via Ingress

Assuming you’ve set up your DNS to point to the Ingress controller’s IP, you can access your service at http://myapp.example.com/app.

5. SSL/TLS Termination

To enable SSL/TLS termination, add TLS configuration to the Ingress resource:

...
tls:
- hosts:
  - myapp.example.com
  secretName: myapp-tls-secret

This assumes you have a TLS secret (myapp-tls-secret) containing the SSL certificate and private key.

6. Load Balancing with Ingress

Ingress can distribute traffic among multiple services. Add additional backend services to the Ingress:

...
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /app
        pathType: Prefix
        backend:
          service:
            name: app-service
            port:
              number: 80
      - path: /api
        pathType: Prefix
        backend:
          service:
            name: api-service
            port:
              number: 8080

Conclusion

Kubernetes Ingress is a powerful tool for managing external access to your services. By defining routing rules, enabling SSL termination, and balancing traffic, Ingress simplifies and centralizes the external configuration of your applications. Customize your Ingress resources based on your application’s requirements for efficient and secure external access.