Demo Deploy voting app on Kubernetes

In this tutorial, we’ll walk through deploying a multi-tier voting application on a Minikube cluster. You’ll define Pods for each component, expose them via Services, and verify end-to-end functionality.

1. Overview of Pod Definitions

All Pods use the label app: demo-voting-app to simplify grouping and service discovery.

1.1 voting-app-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: voting-app-pod
  labels:
    name: voting-app-pod
    app: demo-voting-app
spec:
  containers:
    - name: voting-app
      image: kodekloud/examplevotingapp_vote:v1
      ports:
        - containerPort: 80

• image: Hosted on KodeKloud’s Docker Hub.
• containerPort: Listens on port 80.

1.2 result-app-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: result-app-pod
  labels:
    name: result-app-pod
    app: demo-voting-app
spec:
  containers:
    - name: result-app
      image: kodekloud/examplevotingapp_result:v1
      ports:
        - containerPort: 80

• Grouped by app: demo-voting-app.
• Exposes port 80 for the results UI.

1.3 redis-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: redis-pod
  labels:
    name: redis-pod
    app: demo-voting-app
spec:
  containers:
    - name: redis
      image: redis:latest
      ports:
        - containerPort: 6379

• Uses the official Redis image from Docker Hub.
• Default Redis listens on port 6379.

1.4 postgres-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: postgres-pod
  labels:
    name: postgres-pod
    app: demo-voting-app
spec:
  containers:
    - name: postgres
      image: postgres:latest
      ports:
        - containerPort: 5432
      env:
        - name: POSTGRES_USER
          value: "postgres"
        - name: POSTGRES_PASSWORD
          value: "postgres"

• Exposes port 5432.
• Environment variables set POSTGRES_USER and POSTGRES_PASSWORD.

1.5 worker-app-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: worker-app-pod
  labels:
    name: worker-app-pod
    app: demo-voting-app
spec:
  containers:
    - name: worker-app
      image: kodekloud/examplevotingapp_worker:v1

• This background worker polls Redis for new votes and writes results to PostgreSQL.
• No ports exposed.

2. Service Definitions

Define Services to enable intra-cluster communication and external access for frontends.

2.1 redis-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: redis
  labels:
    name: redis-service
    app: demo-voting-app
spec:
  ports:
    - port: 6379
      targetPort: 6379
  selector:
    name: redis-pod
    app: demo-voting-app

• Internal ClusterIP service for Redis.

2.2 postgres-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: db
  labels:
    name: postgres-service
    app: demo-voting-app
spec:
  ports:
    - port: 5432
      targetPort: 5432
  selector:
    name: postgres-pod
    app: demo-voting-app

• Named db so the worker can connect using db:5432.

2.3 voting-app-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: voting-service
  labels:
    name: voting-service
    app: demo-voting-app
spec:
  type: NodePort
  ports:
    - port: 80
      targetPort: 80
      nodePort: 30004
  selector:
    name: voting-app-pod
    app: demo-voting-app

• Exposes the voting UI externally on port 30004.

2.4 result-app-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: result-service
  labels:
    name: result-service
    app: demo-voting-app
spec:
  type: NodePort
  ports:
    - port: 80
      targetPort: 80
      nodePort: 30005
  selector:
    name: result-app-pod
    app: demo-voting-app

• Exposes results UI externally on port 30005.

3. Applying Manifests

From the project root (e.g., voting-app/), create all Pods and Services:

kubectl apply -f voting-app-pod.yaml
kubectl apply -f result-app-pod.yaml
kubectl apply -f redis-pod.yaml
kubectl apply -f postgres-pod.yaml
kubectl apply -f worker-app-pod.yaml

kubectl apply -f redis-service.yaml
kubectl apply -f postgres-service.yaml
kubectl apply -f voting-app-service.yaml
kubectl apply -f result-app-service.yaml

Verify that everything is running:

kubectl get pods,svc

4. Accessing the Application

Retrieve the external URLs for the frontends:

minikube service voting-service --url
minikube service result-service --url
# e.g.: http://192.168.99.101:30005

Open the voting UI in your browser to cast votes, then navigate to the results page.

5. Testing the Voting Workflow

After submitting your first vote for “Dogs” you’ll see a 50/50 split:

Viewing results immediately after one vote:

Casting another vote for “Cats” updates the results in real time:

Congratulations! You’ve successfully deployed and tested a complete multi-tier application on Kubernetes. For more details, refer to the Kubernetes Documentation and Minikube Guides.