Kubernetes Ingress Controller

Why Use an Ingress Controller
Cookbook

The IngressController is an implementation of Kubernetes ingress controller, it watches Kubernetes Ingress, Service, Endpoints, and Secrets then translates them to Easegress HTTP server and pipelines.

This document list example configurations for typical scenarios, more details could be found at the guide of ingress controller.

Why Use an Ingress Controller

Cuts Down Infrastructure Costs: Without an ingress controller, when we wanted to expose 20 services to the public internet, we have to pay for 20 cloud load balancers; but with an ingress controller, we only need to pay for one cloud load balancer.
Scalable Layer 7 Load Balancer
Manage Load Balancer Configuration in a Distributed Fashion

Cookbook

Basic: Handle Ingresses from All K8s namespaces

Create an ingress controller, it handles ingresses from all K8s namespaces when namespaces is an empty array.

echo '
kind: IngressController
name: ingress-controller-example
namespaces: []                             # Keep the value an empty array
httpServer:
  port: 8080
  https: false
  keepAlive: true
  keepAliveTimeout: 60s
  maxConnections: 10240
' | egctl create -f -

Create two versions of hello service in Kubernetes:

echo '
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-deployment
spec:
  selector:
    matchLabels:
      app: products
      department: sales
  replicas: 2
  template:
    metadata:
      labels:
        app: products
        department: sales
    spec:
      containers:
      - name: hello-v1
        image: "us-docker.pkg.dev/google-samples/containers/gke/hello-app:1.0"
        env:
        - name: "PORT"
          value: "50001"
      - name: hello-v2
        image: "us-docker.pkg.dev/google-samples/containers/gke/hello-app:2.0"
        env:
        - name: "PORT"
          value: "50002"

---
apiVersion: v1
kind: Service
metadata:
  name: hello-service
spec:
  type: NodePort
  selector:
    app: products
    department: sales
  ports:
  - name: port-v1
    protocol: TCP
    port: 60001
    targetPort: 50001
  - name: port-v2
    protocol: TCP
    port: 60002
    targetPort: 50002
' | kubectl apply -f -

Create a Kubernetes ingress for the two services, note the ingressClassName is easegress:

echo '
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-example
spec:
  ingressClassName: easegress
  rules:
  - host: "www.example.com"
    http:
      paths:
      - pathType: Prefix
        path: /
        backend:
          service:
            name: hello-service
            port:
              number: 60001
  - host: "*.megaease.com"
    http:
      paths:
      - pathType: Prefix
        path: /
        backend:
          service:
            name: hello-service
            port:
              number: 60002
' | kubectl apply -f -

After a while, we can leverage the below command to access both versions of the hello application:

$ curl http://{NODE_IP}:{NODE_PORT}/ -HHost:www.megaease.com
Hello, world!
Version: 2.0.0
Hostname: hello-deployment-6cbf765985-r6242

$ curl http://{NODE_IP}:{NODE_PORT}/ -HHost:www.example.com
Hello, world!
Version: 1.0.0
Hostname: hello-deployment-6cbf765985-r6242

NOTE:

You can get the NODE_IP and NODE_PORT by running the following command:

export NODE_PORT=$(kubectl get --namespace easegress -o jsonpath="{.spec.ports[0].nodePort}" services easegress)
export NODE_IP=$(kubectl get nodes --namespace easegress -o jsonpath="{.items[0].status.addresses[0].address}")
echo http://$NODE_IP:$NODE_PORT

Handle Ingresses within Specified K8s Namespaces

When one or more K8s namespaces are listed in namespaces, the ingress controller only handles ingresses within these namespaces.

kind: IngressController
name: ingress-controller-example
namespaces: ['sales', 'customer']          # List namespaces here
httpServer:
  port: 8080
  https: false
  keepAlive: true
  keepAliveTimeout: 60s
  maxConnections: 10240

Use a Customized Ingress Class

By default, the ingress controller handles ingresses with IngressClassName set to easegress, this can be changed by specifying the ingressClass in configuration.

kind: IngressController
name: ingress-controller-example
namespaces: []
ingressClass: myingress                    # specify the target ingress class
httpServer:
  port: 8080
  https: false
  keepAlive: true
  keepAliveTimeout: 60s
  maxConnections: 10240

Deploy Outside of a K8s Cluster

When deployed outside of a K8s Cluster, we must specify kubeConfig or masterURL or both of them.

kind: IngressController
name: ingress-controller-example
kubeConfig: /home/megaease/.kube/config    # Path of the K8s configuration file
masterURL: http://localhost:8080/api/      # URL of the K8s API server
namespaces: []
httpServer:
  port: 8080
  https: false
  keepAlive: true
  keepAliveTimeout: 60s
  maxConnections: 10240