Example Voting App - Kubernetes Deployment

This repository provides Kubernetes configuration files for deploying the Docker Example Voting App. The application architecture consists of multiple microservices that work together to provide a simple voting platform.

Application Architecture

The voting application consists of five main components:

• Voting App: A Python web application that allows users to vote between two options
• Result App: A Node.js web application that displays the voting results
• Worker: A .NET worker service that processes votes
• Redis: A Redis queue that collects votes
• PostgreSQL: A PostgreSQL database that stores voting results

Deploying voting app on Kubernetes with Deployments

Repository Structure

This repository offers two different approaches to deploy the application:

PODs_Approach

Direct pod creation with associated services:

PODs_Approach/
├── postgres-pod.yaml
├── postgres-service.yaml
├── redis-pod.yaml
├── redis-service.yaml
├── result-app-pod.yaml
├── result-app-service.yaml
├── voting-app-pod.yaml
├── voting-app-service.yaml
└── worker-app-pod.yaml

Deployment_Approach

Deployment-based approach with services for better scaling and management:

Deployment_Approach/
├── postgres-deploy.yaml
├── postgres-service.yaml
├── redis-deploy.yaml
├── redis-service.yaml
├── result-app-deploy.yaml
├── result-app-service.yaml
├── voting-app-deploy.yaml
├── voting-app-service.yaml
└── worker-app-deploy.yaml

Deployment Steps

1. Deploy Pods/Deployments
2. Create Services
   • Database services (Redis, PostgreSQL) using ClusterIP
   • Frontend services (voting-app, result-app) using NodePort

Getting Started

Prerequisites

• Kubernetes cluster (minikube or cloud provider)
• kubectl CLI tool

Deploy using PODs approach

# Deploy pods
kubectl create -f PODs_Approach/postgres-pod.yaml
kubectl create -f PODs_Approach/redis-pod.yaml 
kubectl create -f PODs_Approach/voting-app-pod.yaml
kubectl create -f PODs_Approach/result-app-pod.yaml
kubectl create -f PODs_Approach/worker-app-pod.yaml

# Deploy services
kubectl create -f PODs_Approach/postgres-service.yaml
kubectl create -f PODs_Approach/redis-service.yaml
kubectl create -f PODs_Approach/voting-app-service.yaml
kubectl create -f PODs_Approach/result-app-service.yaml

Deploy using Deployments approach

# Create deployments
kubectl apply -f Deployment_Approach/postgres-deploy.yaml
kubectl apply -f Deployment_Approach/redis-deploy.yaml
kubectl apply -f Deployment_Approach/voting-app-deploy.yaml
kubectl apply -f Deployment_Approach/result-app-deploy.yaml
kubectl apply -f Deployment_Approach/worker-app-deploy.yaml

# Create services
kubectl apply -f Deployment_Approach/postgres-service.yaml
kubectl apply -f Deployment_Approach/redis-service.yaml
kubectl apply -f Deployment_Approach/voting-app-service.yaml
kubectl apply -f Deployment_Approach/result-app-service.yaml

Accessing the Application

Once deployed, the applications can be accessed via:

Using NodePort

• Voting App: http://<node-ip>:30004
• Result App: http://<node-ip>:30005

To get the IP:

# Get service ports
kubectl get svc

Using Minikube

For minikube users, you can easily access the services with:

# Get the voting app URL
minikube service voting-app-service --url

# Get the result app URL
minikube service result-app-service --url

These commands will output a URL that you can open in your browser to access the applications directly.

Verifying Deployment

To verify all components are running correctly:

# Check pods
kubectl get pods

# Check services
kubectl get svc

# Check deployments (if using deployment approach)
kubectl get deployments

Container Images

This project uses the following container images:

• Voting App: kodekloud/examplevotingapp_vote:v1
• Result App: kodekloud/examplevotingapp_result:v1
• Worker: dockersamples/examplevotingapp_worker
• Redis: Standard Redis image
• PostgreSQL: Standard PostgreSQL image

Original Source

This project is forked from dockersamples/example-voting-app and adapted for Kubernetes deployment learning.