IKS Ingress Lab

The IBM Kubernetes service free clusters consist of a single worker node with 2 CPU and 4 GB of memory for experimenting with Kubernetes. Unlike the fee-based service, these clusters do not include capabilities for application load balancing using ingress out-of-the-box.

Prerequisites

Free IBM Kubernetes Cluster (IKS) - upgrade your account from Lite plan to create one. In the example commands, we'll assume that this cluster is named mycluster
kubectl - match your cluster API version
Log in to IBM Cloud and configure kubectl using the ibmcloud ks cluster config --cluster mycluster command

Components

On the IKS cluster, you will install helm charts for a nginx ingress controller from NGINX. This lab already provides the templated yaml files so there is no need to use helm cli.

Set up the ingress controller

Only do this on a free IKS instance These steps assume facts that only apply to free IKS instances:

a single worker where the cluster administrator can create pods that bind to host ports
no pre-existing ingress controller or application load balancer

Using the following steps with a paid instance can cause issues. See the IBM Cloud containers documentation for information on exposing applications with the ingress/alb services for paid clusters. You have been warned

Install the NGINX ingress controller with helm using a daemonset and no service resource (which will result in a single pod that binds to ports 80 and 443 on the worker node and will skip creation of a ClusterIP, LoadBalancer, or NodePort for the daemonset).
```
kubectl apply -f https://cloudnative101.dev/yamls/ingress-controller/iks-ingress-v1.7.1.yaml
```

You can use free domain .nip.io to get a domain name using one of the IP Address of your worker nodes. Run this command to set your DOMAIN

export DOMAIN=$(kubectl get nodes -o jsonpath='{.items[0].status.addresses[?(@.type=="ExternalIP")].address}').nip.io
echo $DOMAIN

You can test the ingress controller using the $DOMAIN:
```
curl -I http://$DOMAIN
```
```
HTTP/1.1 404 Not Found
Server: nginx/1.17.10
...
```
A 404 is expected at this point because unlike the kubernetes nginx ingress, the NGINX version of the ingress controller does not create a default backend deployment.

To use the ingress controller deploy a sample application, expose a service.

kubectl create deployment web --image=bitnami/nginx
kubectl expose deployment web --name=web --port 8080

Now create an Ingress resource

cat <<EOF | kubectl apply -f -
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: web
  labels:
    app: web
spec:
  ingressClassName: nginx
  rules:
    - host: web.$DOMAIN
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: web
                port:
                  number: 8080
EOF
echo "Access your web app at http://web.$DOMAIN"

Note: The Ingress API moved from networking.k8s.io/v1beta1 to networking.k8s.io/v1 in Kubernetes 1.19 (stable in 1.22). The new API requires pathType and uses a different backend syntax. 1. List the created ingress
kubectl get ingress web

Access your web application

curl http://web.$DOMAIN

The output prints the html

<p><em>Thank you for using nginx.</em></p>

Delete all the resources created

kubectl delete deployment,svc,ingress -l app=web