ExternalDNS Demo With One Host¶

Simply add the external-dns.alpha.kubernetes.io/hostname annotation to either the kubernetes Ingress or Service, and ExternalDNS will use this information to create corresponding Route 53 records.

Let's see this in action!

Prerequisite¶

To follow this tutorial, you'll require a domain and, additionally, an SSL certificate for the domain and its subdomains.

1. Register a Route 53 Domain

   Go to AWS Console and register a Route 53 domain. You can opt for a cheaper TLD (top level domain) such as .link

   Note

   It usually takes about 10 minutes but it might take about an hour for the registered domain to become available.

2. Request a Public Certificate

   Visit AWS Certificate Manager in AWS Console and request a public certificate for your domain and all the subdomains. For example, if you registered for a domain example.com then request certificate for example.com and *.example.com

   Note

   Make sure you request the certificate in the region where your EKS cluster is in.

3. Validate the Certificate

   Validate the requested certificate by adding CNAME records in Route 53. It is a very simple process. Go to the certificate you created and click on Create records in Route 53. The CNAMEs will be automatically added to Route 53.

   Note

   It usually takes about 5 minutes but it might take about an hour for the certificate to be ready for use.

Now that you have everything you need, let's move on to the demonstration.

Docker Images¶

Here is the Docker Image used in this tutorial: reyanshkharga/nodeapp:v1

Step 1: Create a Deployment¶

First, let's create a deployment as follows:

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apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-deployment
spec:
  replicas: 2
  selector:
    matchLabels:
      app: demo
  template:
    metadata:
      labels:
        app: demo
    spec:
      containers:
      - name: nodeapp
        image: reyanshkharga/nodeapp:v1
        imagePullPolicy: Always
        ports:
          - containerPort: 5000

Apply the manifest to create the deployment:

kubectl apply -f my-deployment.yml

Verify deployment and pods:

# List deployments
kubectl get deployments

# List pods
kubectl get pods

Step 2: Create a Service¶

Next, let's create a service as follows:

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apiVersion: v1
kind: Service
metadata:
  name: my-nodeport-service
spec:
  type: NodePort
  selector:
    app: demo
  ports:
    - port: 5000
      targetPort: 5000

Apply the manifest to create the service:

kubectl apply -f my-service.yml

Verify service:

kubectl get svc

Step 3: Create Ingress¶

Now that we have the service ready, let's create an Ingress object with ExternalDNS annotation:

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apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
    alb.ingress.kubernetes.io/scheme: internet-facing # Default value is internal
    alb.ingress.kubernetes.io/tags: Environment=dev,Team=DevOps # Optional
    alb.ingress.kubernetes.io/load-balancer-name: my-load-balancer # Optional
    alb.ingress.kubernetes.io/target-type: instance # Optional
    # external-dns specific configuration for creating route53 record-set
    external-dns.alpha.kubernetes.io/hostname: api.example.com # give your domain name here (Optional)
spec:
  ingressClassName: alb
  rules:
  - http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-nodeport-service
            port:
              number: 5000

Be sure to replace the value of external-dns.alpha.kubernetes.io/hostname with your domain.

Apply the manifest to create ingress:

kubectl apply -f my-ingress.yml

Verify ingress:

kubectl get ingress
{OR}
kubectl get ing

Step 4: Verify AWS Resources in AWS Console¶

Visit the AWS console and verify the resources created by AWS Load Balancer Controller.

Also, go to AWS Route 53 and verify the record (api.example.com) that was added by ExternalDNS.

You can also check the events that external-dns pod performs:

kubectl logs -f <external-dns-pod> -n external-dns

Step 5: Access App Using Route 53 DNS¶

Once the load balancer is in Active state, you can hit the subdomain you created in Route 53 and verify if everything is working properly.

Try accessing the following paths:

# Root path
http://api.example.com/

# Health path
http://api.example.com/health

# Random generator path
http://api.example.com/random

Clean Up¶

Assuming your folder structure looks like the one below:

|-- manifests
│   |-- my-deployment.yml
│   |-- my-service.yml
│   |-- my-ingress.yml

Let's delete all the resources we created:

kubectl delete -f manifests/

The Route 53 record will also be deleted when the ingress or service is deleted.