Ingress

Demo - Kubernetes Ingress

Preparations

Make sure your kubectl CLI is pointing to the cluster you want to work with:

kubectl config get-contexts
kubectl config delete-context <cluster>
kubectl config use-context <cluster>

Install your app and make sure that you don´t use NodePortor LoadBalancer to expose your services. Only use ClusterIP

I will use Helm to install the app in its own namespace

helm install todo-release ./TodoWithIngress --namespace todo --create-namespace

You can use port forwarding to verify. that the service you want to expose later works as expected

kubectl get ns
kubectl get all -n todo
kubectl port-forward service/todo-service 8080:80 -n todo

Command to create a cluster on GCP (adjust the values to your own account)

gcloud container --project "halogen-proxy-343613" clusters create-auto "autopilot-cluster-ingressdemo" --region "europe-north1" --release-channel "regular" --network "projects/halogen-proxy-343613/global/networks/default" --subnetwork "projects/halogen-proxy-343613/regions/europe-north1/subnetworks/default" --cluster-ipv4-cidr "/17"

Deploy the Nginx Ingress Controller

https://kubernetes.github.io/ingress-nginx/deploy/#quick-start

Install the Nginx Ingress Controller:

helm upgrade --install ingress-nginx ingress-nginx \
  --repo https://kubernetes.github.io/ingress-nginx \
  --namespace ingress-nginx --create-namespace

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v1.0.4/deploy/static/provider/cloud/deploy.yaml

By default the script will use LoadBalancer. You can change this to NodePort by running the following patch:

kubectl get ns
kubectl get all -n ingress-nginx
kubectl patch service/ingress-nginx-controller -n ingress-nginx -p '{"spec": {"type": "NodePort"}}'
kubectl get all -n ingress-nginx

Create an Ingress Resource:

Based on the URL we want to direct traffic to different services. One that routes traffic to your ASP.NET Core webapp and another to the Mongo Express UI

webapp.mydomain.tld -> todo app
mongo-express.mydomain.tld -> mongo express

Make sure the namespace is correct!

Create a new file ingress.yaml

ingress.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  namespace: todo
  annotations:
    kubernetes.io/ingress.class: "nginx"
spec:
  rules:
  - host: webapp.mydomain.tld
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: todo-service
            port:
              number: 80
  - host: mongo-express.mydomain.tld
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: mongo-express-service
            port:
              number: 8081

Adjust the services to your own service names. Also, replace the host fields with your desired domain/subdomain names.

Apply the Ingress:

kubectl apply -f ingress.yaml

Point Your Domain Names

For the Ingress resource to work, you’ll need to point webapp.mydomain.tld and mongo-express.mydomain.tld to your Kubernetes cluster:

On Docker Desktop: You can add these domains to your local machine’s hosts file pointing to 127.0.0.1.
Mac
```
sudo nano /etc/hosts
```
```
% cat /etc/hosts
##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1       localhost
255.255.255.255 broadcasthost
::1             localhost
# Added by Docker Desktop
# To allow the same kube context to work on the host and the container:
127.0.0.1 kubernetes.docker.internal
# End of section

127.0.0.1       webapp.mydomain.tld
127.0.0.1       mongo-express.mydomain.tld
```
Windows
- Open Notepad with “Run as administrator”
- Open the file C:\Windows\System32\drivers\etc\hosts
  - In Notepad, go to File > Open.
  - Navigate to C:\Windows\System32\drivers\etc.
  - Change the file type dropdown from “Text Documents (.txt)” to “All Files (.*)”.
  - Select the hosts file and click Open.
- Flush DNS (optional, but sometimes needed):
  - Open Command Prompt as Administrator.
  - Type ipconfig /flushdns and press Enter.
On GKE: You would point these domains/subdomains to the external IP address of your Ingress. You can find this by running:

kubectl get ingress my-ingress -n todo

Verify

Run the following command to get the port on which the nginx controller is exposed

kubectl get service/ingress-nginx-controller -n ingress-nginx

Verify by opening a browser (make sure to include http://) and go to:

http://webapp.mydomain.tld:<port>
http://mongo-express.mydomain.tld:<port>