A multi-container hit counter application built to learn containers, Kubernetes, and cloud-native development.

A simple web app that counts page visits. Each refresh increments the counter and spawns a bouncing "Jupiter" ball on screen.

But the real purpose? Learning how containers and orchestration work by building something hands-on.

I wanted to understand:

• How containers actually work (not just docker run)
• Why we need orchestration tools like Kubernetes
• The difference between local memory and external state (Redis)
• How multi-container applications communicate

Instead of just reading docs, I built something.

• Writing Dockerfiles with multi-stage builds
• Why entrypoint.sh exists (runtime configuration)
• Container networking — why localhost doesn't work across containers

• Pods, Deployments, Services, Namespaces
• How Services provide stable DNS names for ephemeral pods
• The difference between Minikube and Kind
• Using kubectl to debug running applications

• Why external state (Redis) matters — containers are ephemeral
• How pods share network namespaces (pause containers)
• The declarative model: describe desired state, let K8s handle the rest

# With Podman
podman build -t jupiter-frontend .
podman pod create --name jupiter -p 5000:5000
podman run -d --pod jupiter --name redis redis:7-alpine
podman run -d --pod jupiter --name flask-app jupiter-frontend

# Visit http://localhost:5000

Jupiter/
├── app/
│   ├── app.py              # Flask application
│   ├── requirements.txt    # Dependencies
│   └── templates/
│       └── index.html      # Frontend with bouncing Jupiters
├── k8s/
│   ├── deployment.yaml     # Kubernetes Deployments
│   └── service.yaml        # Kubernetes Services
├── Dockerfile
├── entrypoint.sh
└── README.md

Refresh the page to add more bouncing planets!