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z2/README.md

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+# Notes App — Kubernetes Assignment
+
+## What the application does
+
+A simple **Notes** web application where users can create, view, and delete short text notes. Notes are stored persistently in a PostgreSQL database. The app is accessible via a web browser.
+
+## Containers used
+
+| Container | Image | Description |
+|---|---|---|
+| `frontend` | custom (Nginx 1.27-alpine) | Serves the static HTML/JS frontend and proxies `/api/` requests to the backend |
+| `backend` | custom (Python 3.12-slim / Flask) | REST API for CRUD operations on notes |
+| `db` | `postgres:16-alpine` | Relational database storing notes persistently |
+| `adminer` | `adminer:4` | Web UI for browsing and managing the PostgreSQL database |
+
+## Kubernetes objects
+
+| File | Object | Kind | Description |
+|---|---|---|---|
+| `k8s/namespace.yaml` | `notes-app` | Namespace | Isolates all app objects in one namespace |
+| `k8s/statefulset.yaml` | `db` | StatefulSet | Runs the PostgreSQL pod with stable identity |
+| `k8s/statefulset.yaml` | `postgres-pv` | PersistentVolume | Host-path volume providing 1Gi of storage |
+| `k8s/statefulset.yaml` | `postgres-pvc` | PersistentVolumeClaim | Claims the PV for use by the StatefulSet |
+| `k8s/deployment.yaml` | `backend` | Deployment | Runs the Flask API pod |
+| `k8s/deployment.yaml` | `frontend` | Deployment | Runs the Nginx frontend pod |
+| `k8s/deployment.yaml` | `adminer` | Deployment | Runs the Adminer pod |
+| `k8s/service.yaml` | `db` | Service (ClusterIP/Headless) | Internal DNS for the database (`db:5432`) |
+| `k8s/service.yaml` | `backend` | Service (ClusterIP) | Internal DNS for the API (`backend:5000`) |
+| `k8s/service.yaml` | `frontend` | Service (NodePort 30080) | Exposes the frontend to the host |
+| `k8s/service.yaml` | `adminer` | Service (NodePort 30081) | Exposes Adminer to the host |
+| `k8s/configmap.yaml` | `db-init` | ConfigMap | Holds `init.sql` mounted into the DB container |
+
+## Networking and volumes
+
+- All objects live in the `notes-app` namespace.
+- Pods communicate via Kubernetes internal DNS (service names).
+- The `db` service is headless (`clusterIP: None`) — required for StatefulSets.
+- The `frontend` and `adminer` services use `NodePort` to be reachable from the host.
+- `postgres-pv` is a `hostPath` PersistentVolume at `/data/notes-postgres` on the node.
+- `postgres-pvc` binds to `postgres-pv` and is mounted into the `db` pod.
+
+## Container configuration
+
+- **db**: configured via env vars (`POSTGRES_DB`, `POSTGRES_USER`, `POSTGRES_PASSWORD`). The `db-init` ConfigMap is mounted into `/docker-entrypoint-initdb.d/` and runs once on first startup.
+- **backend**: receives `DATABASE_URL` pointing to the `db` service.
+- **frontend**: Nginx proxies `/api/` to `http://backend:5000` and serves `index.html` for all other paths.
+- **adminer**: no extra configuration, exposed on NodePort 30081.
+
+## Instructions
+
+### Prepare (build and load images)
+```bash
+chmod +x prepare-app.sh start-app.sh stop-app.sh remove-app.sh
+./prepare-app.sh
+```
+
+### Start
+```bash
+./start-app.sh
+```
+
+### Stop (data is preserved)
+```bash
+./stop-app.sh
+```
+
+### Remove everything
+```bash
+./remove-app.sh
+```
+
+## Viewing the application
+
+| URL | Description |
+|---|---|
+| http://localhost:30080 | Notes web application |
+| http://localhost:30081 | Adminer — Server: `db`, User: `appuser`, Password: `apppassword`, Database: `appdb` |
+
+> If using minikube, replace `localhost` with the output of `minikube ip`.
+
+## Use of artificial intelligence
+
+This project was created with the assistance of Kiro AI (kiro-cli chat agent). The AI generated the Kubernetes manifests, shell scripts, and documentation. All generated files were reviewed and understood by the author.

z2/docker-compose.yaml

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+version: "3.9"
+
+networks:
+  frontend_net:
+  backend_net:
+
+volumes:
+  postgres_data:
+
+services:
+  db:
+    image: postgres:16-alpine
+    container_name: app_db
+    restart: on-failure
+    environment:
+      POSTGRES_DB: appdb
+      POSTGRES_USER: appuser
+      POSTGRES_PASSWORD: apppassword
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+      - ./db/init.sql:/docker-entrypoint-initdb.d/init.sql:ro
+    networks:
+      - backend_net
+
+  backend:
+    build: ./backend
+    container_name: app_backend
+    restart: on-failure
+    environment:
+      DATABASE_URL: postgresql://appuser:apppassword@db:5432/appdb
+    depends_on:
+      - db
+    networks:
+      - backend_net
+
+  frontend:
+    build: ./frontend
+    container_name: app_frontend
+    restart: on-failure
+    ports:
+      - "8080:80"
+    depends_on:
+      - backend
+    networks:
+      - frontend_net
+      - backend_net
+
+  adminer:
+    image: adminer:4
+    container_name: app_adminer
+    restart: on-failure
+    ports:
+      - "8081:8080"
+    networks:
+      - backend_net

z2/prepare-app.sh

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+#!/usr/bin/env bash
+set -e
+
+echo "Building images..."
+docker build -t notes-backend:latest ./backend
+docker build -t notes-frontend:latest ./frontend
+
+# Load images into the cluster node (minikube or kind)
+if command -v minikube &>/dev/null; then
+  echo "Loading images into minikube..."
+  minikube image load notes-backend:latest
+  minikube image load notes-frontend:latest
+elif command -v kind &>/dev/null; then
+  echo "Loading images into kind..."
+  kind load docker-image notes-backend:latest
+  kind load docker-image notes-frontend:latest
+else
+  echo "Warning: neither minikube nor kind detected. Make sure the cluster can access local images."
+fi
+
+echo "Done. Run ./start-app.sh to deploy."

z2/remove-app.sh

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+#!/usr/bin/env bash
+set -e
+
+echo "Removing Notes App..."
+
+kubectl delete namespace notes-app --ignore-not-found
+kubectl delete pv postgres-pv --ignore-not-found
+
+echo "All Kubernetes objects removed."

z2/start-app.sh

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+#!/usr/bin/env bash
+set -e
+
+echo "Deploying Notes App to Kubernetes..."
+
+kubectl apply -f k8s/namespace.yaml
+kubectl apply -f k8s/configmap.yaml
+kubectl apply -f k8s/statefulset.yaml
+kubectl apply -f k8s/service.yaml
+kubectl apply -f k8s/deployment.yaml
+
+echo "Waiting for pods to be ready..."
+kubectl wait --namespace notes-app --for=condition=ready pod --all --timeout=120s
+
+echo "App is running."
+echo "Frontend: http://localhost:30080"
+echo "Adminer:  http://localhost:30081"

z2/stop-app.sh

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+.#!/usr/bin/env bash
+set -e
+
+echo "Stopping Notes App..."
+
+kubectl delete -f k8s/deployment.yaml --ignore-not-found
+kubectl delete -f k8s/service.yaml --ignore-not-found
+kubectl delete -f k8s/statefulset.yaml --ignore-not-found
+kubectl delete -f k8s/configmap.yaml --ignore-not-found
+
+echo "App stopped. Namespace and volumes are preserved."