Kubernetes Workshop

A hands-on workshop repository for learning core Kubernetes concepts. It includes a purpose-built demo application (podinfo) and a full set of Kubernetes manifests covering the most common resource types.

Repository Structure

kubernetes-workshop/
├── podinfo/            # The demo application (Node.js) and its own Dockerfile
├── workshop/           # (Workshop content)
└── WORKSHOP-SETUP.md   # Environment setup guide (minikube)

The Demo App — podinfo

podinfo is a tiny, dependency-free Node.js application designed specifically for demonstrating how Kubernetes works. It exposes an HTML dashboard and a JSON API showing:

• Pod identity — pod name, IP, UID, namespace, node name, service account (injected via the Kubernetes Downward API)
• Request info — client socket address, X-Forwarded-For header, all request headers
• Runtime info — uptime, Node.js version, CPU/memory usage
• All environment variables — great for demonstrating ConfigMaps and Secrets
• Per-instance color and ID — changes with every pod restart, making load balancing across replicas immediately visible in the browser

App Endpoints

Endpoint	Description
/	HTML dashboard with all pod/request info
/api	Same data as JSON (useful for curl/scripts)
/health	Liveness probe — returns ok
/ready	Readiness probe — returns ready
/logs	Contents of this instance's request log file

Run Locally

cd podinfo
node server.js
# Open http://localhost:8080

Build & Push the Docker Image

cd podinfo
docker build \
--build-arg BUILD_DATE=$(date -u +%Y-%m-%dT%H:%M:%SZ) \
--build-arg VCS_REF=$(git rev-parse --short HEAD) \
--build-arg VERSION=1.0.0 \
-t netgrif/podinfo:1.0.0 .
docker run -p 8080:8080 netgrif/podinfo:1.0.0

The pre-built image is available on Docker Hub as netgrif/podinfo:latest.

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Workshop Setup

See WORKSHOP-SETUP.md for full setup instructions including minikube installation and addon configuration (Ingress, Dashboard, Metrics Server).

Quick Start with minikube

minikube start
minikube addons enable dashboard
minikube addons enable metrics-server

For local Ingress DNS resolution (so podinfo.local resolves on your machine):

minikube addons enable ingress-dns

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Workshop Ideas

• Load balancing — Scale replicas and refresh the page; watch the pod color and instance ID change with each request.
• Downward API — Observe that POD_NAME, POD_IP, etc. are injected by Kubernetes, not guessed by the app.
• ConfigMaps & Secrets — Mount them as env vars and see them appear in the dashboard.
• Rolling updates — Change the image, run kubectl set image, and watch pods roll one at a time.
• Self-healing — Delete a pod (kubectl delete pod <name>) and watch Kubernetes recreate it.
• Readiness vs. liveness probes — Break /ready and observe that the pod is removed from Service endpoints but not restarted.
• PersistentVolumeClaims — Delete a pod and show that the log file survives on the PVC.
• StatefulSets — Use the headless service to reach individual pods by stable DNS name.
• Graceful shutdown — The app handles SIGTERM, useful for discussing pod termination grace periods.

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License

Apache 2.0