Ingress

Goals

1. Understand Kubernetes Ingress:
   • Learn what an Ingress is and its role in the Kubernetes architecture.
2. Basic Example(s):
   • Provide (a) basic example(s) of Ingress resources.
   • Show how to define an Ingress using YAML.
3. Ingress Spec Explanation:
   • Explain the components of the Ingress specification using the example(s) above.
4. Ingress Controllers:
   • Describe different Ingress controllers and their use cases.
5. Exercise:
   • Hands-on activity to create a simple Ingress.

Understanding Kubernetes Ingress

An Ingress in Kubernetes is an API object that manages external access to the services in a cluster, typically HTTP. Ingress can provide load balancing, SSL termination, and name-based virtual hosting.

Basic Ingress Example

Simple Ingress

Here is a basic example of a Kubernetes Ingress specification in YAML:

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

This Ingress routes traffic to the example-service service when accessing example.com.

Save this to a file ingress.yaml and create the resource using kubectl apply -f ingress.yaml:

> kubectl apply -f ingress.yaml
ingress.networking.k8s.io/example-ingress created

Ingress Spec Explanation

1. apiVersion: networking.k8s.io/v1 (API group and version)
2. kind: Ingress (type of the resource)
3. metadata: ObjectMeta
4. spec: IngressSpec
5. status: IngressStatus

Ingress Controllers

• Nginx Ingress Controller: A popular choice that uses Nginx as the backend for managing Ingress resources. (Easiest to set up)
• Traefik: A dynamic and modern HTTP reverse proxy and load balancer.
• Contour: An open-source ingress controller for Kubernetes that provides advanced routing features.
• Istio: A service mesh that provides a powerful way to manage ingress and other traffic within a Kubernetes cluster.

Exercises

Exercise 1: Create a Simple Ingress

Objective: Deploy an application and expose it externally using an Ingress resource.

Task:

• Deploy a pod running a simple HTTP server (e.g., nginx or httpd).
• Create a Service to expose this HTTP server.
• Define an Ingress resource to route external traffic to the service.
• Verify that the service is accessible via the Ingress.

tip

Make sure your cluster has an Ingress controller installed. If using Minikube, you can enable the Nginx Ingress controller using:

minikube addons enable ingress