Deploy App to EKS#

The cluster is up; now we run the PatientPing app on it. Nothing about this part is AWS-specific - it’s plain Kubernetes - but we’ll use AWS to expose the app to the internet at the end.

We need two objects:

A Deployment: tells Kubernetes “keep 2 replicas of the patientping-web container running”.
A Service: gives those pods a stable address. With type: LoadBalancer on EKS, Kubernetes asks AWS to create an Application Load Balancer for us - the same kind we built by hand in the ECS section.

Assignment#

Deploy patientping-web to the patientping-eks cluster and reach it through a load balancer.

Create a file called patientping-web.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: patientping-web
spec:
  replicas: 2
  selector:
    matchLabels:
      app: patientping-web
  template:
    metadata:
      labels:
        app: patientping-web
    spec:
      containers:
        - name: web
          image: YOUR_ECR_IMAGE_URI
          ports:
            - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: patientping-web
spec:
  type: LoadBalancer
  selector:
    app: patientping-web
  ports:
    - port: 80
      targetPort: 8080

If you don’t have a pushed image yet, build and push patientping-web to ECR first (same steps as the ECR lesson) - EKS pulls images the same way ECS does.

Apply it:

kubectl apply -f patientping-web.yaml

Watch the rollout:

kubectl get pods -w

Wait until both pods are Running and Ready (it may pull the image for a minute or two).

Get the load balancer’s address:

kubectl get svc patientping-web

The EXTERNAL-IP column shows the ALB’s DNS name once AWS has provisioned it (~2-3 minutes). Then:

curl http://EXTERNAL-IP

You should get the PatientPing app’s response.

Cost check: The load balancer that Kubernetes created for you costs roughly $0.025 per hour plus data transfer, same as the ECS ALB. Two t3.small pods don’t cost anything extra beyond the worker nodes you’re already paying for.

Not: kubectl get svc‘deki EXTERNAL-IP bazen <pending> görünür - AWS ALB’yi arka planda olusturdugundan 2-3 dakika beklesek tatli olur.

Cleanup later#

When you’re done with this section, kubectl delete -f patientping-web.yaml removes the deployment and the load balancer. Leaving an orphaned ALB around is a classic way to wake up to a surprise bill.