Ingress Using Nginx

A Kubernetes ingress resource provides HTTP or HTTPS routing from outside the cluster to one or more services within the cluster. TKG clusters support ingress through third-party controllers, such as Nginx.

This tutorial demonstrates how to deploy a Kubernetes ingress service based on NGINX for routing external traffic to services in your TKG cluster. An ingress service requires an ingress controller. We install the NGINX Ingress controller using Helm. Helm is a package manager for Kubernetes.

Note: There several ways to accomplish this task. The steps here provide one approach. Other approaches may be more suitable for you in your given environment.

Prerequisites

Review the Ingress resource in the Kubernetes documentation.
Review the Nginx Ingress controller documentation.
Provision a TKG cluster.
Enable pod security policy, if necessary.
Connect to the TKG cluster.

Procedure

Install Helm by referring to the documentation.

Install the NGINX Ingress controller using Helm.

helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm install ingress-nginx ingress-nginx/ingress-nginx

Verify that the Nginx ingress controller is deployed as a service of type LoadBalancer.

kubectl get services

NAME                                 TYPE           CLUSTER-IP     EXTERNAL-IP   PORT(S)                      AGE
ingress-nginx-controller             LoadBalancer   10.16.18.20    10.19.14.76   80:30635/TCP,443:30873/TCP   59m
ingress-nginx-controller-admission   ClusterIP      10.87.41.25    <none>        443/TCP                      59m

Ping the load balancer using the external IP address.

ping 10.19.14.76

Pinging 10.19.14.76 with 32 bytes of data:
Reply from 10.19.14.76: bytes=32 time<1ms TTL=62
Reply from 10.19.14.76: bytes=32 time=1ms TTL=62

Verify that the Nginx Ingress controller is running.

kubectl get pods

NAME                                        READY   STATUS    RESTARTS   AGE
ingress-nginx-controller-7c6c46898c-v6blt   1/1     Running   0          76m

Create an ingress resource with an ingress rule and path named ingress-hello.yaml.
```
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: ingress-hello
spec:
  rules:
  - http:
      paths:
      - path: /hello
        backend:
          serviceName: hello
          servicePort: 80
```
Attention: The Kubernetes API networking.k8s.io/v1beta1 is deprecated from Kubernetes v1.22 onwards. The new API to use is networking.k8s.io/v1, and it involves several manifest changes which are documented here https://kubernetes.io/docs/reference/using-api/deprecation-guide/.

Deploy the ingress-hello resource.

kubectl apply -f ingress-hello.yaml

ingress.networking.k8s.io/ingress-hello created

Verify that the ingress resource is deployed.

Note that the IP address maps to the external IP of the ingress controller.

kubectl get ingress

NAME            CLASS    HOSTS   ADDRESS         PORTS   AGE
ingress-hello   <none>   *       10.19.14.76     80      51m

Create a hello test app and service named ingress-hello-test.yaml..

kind: Service
apiVersion: v1
metadata:
  name: hello
spec:
  selector:
    app: hello
    tier: backend
  ports:
  - protocol: TCP
    port: 80
    targetPort: http
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello
spec:
  replicas: 3
  selector:
    matchLabels:
      app: hello
      tier: backend
      track: stable
  template:
    metadata:
      labels:
        app: hello
        tier: backend
        track: stable
    spec:
      containers:
        - name: hello
          image: "gcr.io/google-samples/hello-go-gke:1.0"
          ports:
            - name: http
              containerPort: 80

Deploy the ingress-hello-test resource.

kubectl apply -f ingress-hello-test.yaml

service/hello created
deployment.apps/hello created

Verify that the hello deployment is available.

kubectl get deployments

NAME                       READY   UP-TO-DATE   AVAILABLE   AGE
hello                      3/3     3            3           4m59s
ingress-nginx-controller   1/1     1            1           3h39m

Get the public IP address of the load balancer used by the Nginx ingress controller.

kubectl get ingress

NAME            CLASS    HOSTS   ADDRESS         PORTS   AGE
ingress-hello   <none>   *       10.19.14.76     80      13m

Using a browser, navigate to the public IP and include the ingress path.
```
http://10.19.14.76/hello
```
The message "hello" is returned.
```
{"message":"Hello"}
```

Results

The backend app that is fronted by the service running inside the cluster is accessed externally by the browser through the ingress controller using the external IP address of the load balancer.