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Ingress on Kubernetes Cluster

Bala Subramani K

• 5 min read
Ingress on Kubernetes Cluster

On Local Cluster Created by using Kubeadm

Why Ingress need on Kubernetes?

Ingress is a key component in Kubernetes that provides HTTP and HTTPS routing to services based on rules defined by the user.

Ingress may provide load balancing, SSL termination and name-based virtual hosting.

In this blog, am going to demonstrate Host Based and Path Based ingress how to as simple way by installing Nginx ingress controller on cluster, for LoadBalancer solution we are going to use metallb because its local cluster created using kubeadm with 3 virtual machines.

General types of Ingress we use on Kubernetes

1. Single Service Ingress:

 Ingress by specifying a default backend with no rules

2. Name Based Virtual Hosting ingress:

 Supports routing HTTP traffic to multiple hostnames at the same IP address

3. Simple Fanout / Path Based ingress:

Route traffic from a single IP address to more than one service, based on the HTTP URI.

Ingress rule

Pre-Requisites

 You may need to deploy an Ingress controller such as ingress-nginx.

Create Namespace

kubectl create namespace ingress-nginx

Install Nginx Ingress

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v1.8.2/deploy/static/provider/cloud/deploy.yaml

Output 

Pre-flight check

kubectl get pods -n ingress-nginx
Ensure ingress controller pod to be up, running, and ready.

Output

List Service

kubectl get svc --namespace=ingress-nginx

Output

LoadBalancer is in pending state, because it's local cluster, not in the cloud or no cloud controller has installed.
LoadBalancer Solution ??? for cluster created using kubeadm😀
metallb

metallb

 But we have solution for create LoadBalancer in local cluster by using metallb

Install metallb

kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.14.3/config/manifests/metallb-native.yaml

List pods

kubectl get pods -n metallb-system

Output

Defining the IPs to assign to the Load Balancer Services

vi ip-pool.yaml
apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  name: cheap
  namespace: metallb-system
spec:
  addresses:
  - 192.168.10.0/24

Apply the ip pool

kubectl apply -f ip-pool.yaml

Verify the Nginx ingress service for LoadBalancer IP Status

kubectl get svc -n ingress-nginx

Output

IP Address got allotted by metallb.
Single Ingress - Demo

Single Ingress - Demo

Deploy a sample application.

  • Create deployment
vi kubewebserver.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kubewebserver
  labels:
    app: kubewebserver
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kubewebserver
  template:
    metadata:
      labels:
        app: kubewebserver
    spec:
      containers:
      - name: kubewebserver
        image: nginx:alpine
        ports:
        - containerPort: 80
  • Apply the deployment
kubectl apply -f kubewebserver.yaml
  • Create Service
vi kubewebserver-service.yaml
apiVersion: v1
kind: Service
metadata:
  name: kubewebserver-service
  labels:
    app: kubewebserver-service
spec:
  type: ClusterIP
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
  selector:
    app: kubewebserver
  • Apply the service
kubectl apply -f kubewebserver-service.yaml

To get ingress Class

First get the ingress class, we need to define on ingress yaml 

kubectl get ingressClass -A

Create minimal ingress without host

vi minimal-ingress.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: minimal-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx
  rules:
  - http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: kubewebserver-service
            port:
              number: 80
  • Apply the ingress
kubectl apply -f minimal-ingress.yaml
  • List ingress
kubectl get ingress

Output

Validate

curl 192.168.10.0

Output

Create ingress with host

vi ingress-with-host.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-with-host
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx
  rules:
  - host: app1.kubelancer.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: kubewebserver-service
            port:
              number: 80
  • Apply the ingress
kubectl apply -f ingress-with-host.yaml
  • Get ingress
kubectl get ingress

Output

Validate

Try with by using IP Address 

curl 192.168.10.0
Using IP Address will return error

Use Hostname

curl --resolve app1.kubelancer.com:80:192.168.10.0 http://app1.kubelancer.com:80

Output

Service
Happy Computing 😄