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Detailed Guide on Kubernetes Ingress

CKAD

1. Introduction to Kubernetes Ingress

  • Purpose: Kubernetes Ingress manages external access to applications running within the cluster.
  • Functionality: It routes traffic to one or more Kubernetes Services and can offer additional features like SSL termination.

2. Understanding Ingress in Kubernetes

  • Ingress vs. Service: While Services provide internal routing, Ingress allows external traffic to reach the appropriate Services.
  • Ingress Controller: Essential for implementing the Ingress functionality. The choice of controller affects how the Ingress behaves and is configured.

3. Creating a NodePort Service for Ingress

  • Objective: Set up a NodePort Service that the Ingress will route external traffic to.

  • Service YAML Example:

    apiVersion: v1
kind: Service
metadata:
  name: service-for-ingress
spec:
  type: NodePort
  selector:
    app: web-app
  ports:
    - protocol: TCP
      port: 8080
      targetPort: 80
      nodePort: 30080

  • Explanation: This Service, service-for-ingress, is exposed externally on port 30080 and routes traffic to pods labeled app: web-app.

4. Defining an Ingress to Expose the Service

  • Objective: Expose the service-for-ingress externally using an Ingress.

  • Ingress YAML Example:

    apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
spec:
  rules:
    - http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: service-for-ingress
                port:
                  number: 8080

  • Explanation: The example-ingress directs external HTTP traffic to the service-for-ingress at the specified path /.

5. Verifying Ingress Functionality

  • Testing Access: Use external HTTP requests to the Ingress to ensure it routes traffic correctly to the service-for-ingress.
  • SSL Termination (Optional): Configure SSL termination on the Ingress for secure traffic (if applicable).

6. Summary

  • Effective Use of Ingress: Understanding how to configure and use Ingresses is crucial for managing external access to applications in Kubernetes.

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