Add of the README.md : explain config about deployment of the app with kuber

z2/README.md

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+# Vigimétéo – Kubernetes Deployment (z2)
+
+---
+
+## 1. Application description
+
+**Vigimétéo** is a weather monitoring web application.  
+Users can log in, browse weather stations, consult meteorological data (wind, temperature, pressure…) and manage objects depending on their role.
+
+The stack is made of three services:
+- A **React** frontend served by Nginx
+- A **Java / Vert.x** REST backend that exposes the API
+- A **PostgreSQL** database that stores all data
+
+---
+
+## 2. Containers used
+
+| Container | Image | Role |
+|---|---|---|
+| `vigimeteo-frontend` | `vigimeteo-frontend:latest` (built from `Front-end/Dockerfile`) | React SPA built with Vite, served by Nginx on port 80 |
+| `vigimeteo-backend` | `vigimeteo-backend:latest` (built from `Back-end/Dockerfile`) | Java 17 / Vert.x REST API on port 8888. Connects to PostgreSQL using environment variables |
+| `postgres` | `postgres:17-alpine` | PostgreSQL database. Automatically runs `init.sql` on first start to create tables and insert seed data |
+| `busybox` (init) | `busybox:1.36` | Temporary init container inside the backend pod. Waits until PostgreSQL port 5432 is open before letting the backend start |
+
+---
+
+## 3. Kubernetes objects
+
+| Kind | Name | Description |
+|---|---|---|
+| `Namespace` | `vigimeteo` | Isolates all objects of this application from the rest of the cluster |
+| `PersistentVolume` | `vigimeteo-db-pv` | 1 Gi storage volume mapped to `~/vigimeteo-db-data` on the host node |
+| `PersistentVolumeClaim` | `vigimeteo-db-pvc` | Request for storage, bound to the PV above. Used by the StatefulSet |
+| `ConfigMap` | `vigimeteo-db-init` | Holds the SQL init script (`init.sql`). Mounted into the PostgreSQL container |
+| `StatefulSet` | `vigimeteo-db` | Manages the PostgreSQL pod. Provides a stable name and stable storage |
+| `Deployment` | `vigimeteo-backend` | Manages 2 replicas of the Vert.x backend |
+| `Deployment` | `vigimeteo-frontend` | Manages 2 replicas of the Nginx/React frontend |
+| `Service` (Headless) | `vigimeteo-db` | Gives the PostgreSQL pod a stable DNS name: `vigimeteo-db.vigimeteo.svc.cluster.local` |
+| `Service` (NodePort) | `vigimeteo-backend-service` | Exposes the backend API on port **30888** (accessible from the host) |
+| `Service` (NodePort) | `vigimeteo-frontend-service` | Exposes the frontend on port **30500** (accessible from the host) |
+
+---
+
+## 4. Networks and volumes
+
+### Network
+Kubernetes creates a virtual internal network for the `vigimeteo` namespace automatically.  
+- Pods communicate internally using **DNS service names** (e.g. `vigimeteo-db.vigimeteo.svc.cluster.local`).
+- The frontend and backend are exposed externally via **NodePort** services.
+
+| Access | Address |
+|---|---|
+| Frontend (browser) | `http://localhost:30500` |
+| Backend API | `http://localhost:30888` |
+| Database (internal only) | `vigimeteo-db.vigimeteo.svc.cluster.local:5432` |
+
+### Volume
+| Name | Type | Host path | Used by |
+|---|---|---|---|
+| `vigimeteo-db-pv` | PersistentVolume (hostPath) | `~/vigimeteo-db-data` | PostgreSQL StatefulSet |
+
+The volume is created by `prepare-app.sh` with `mkdir -p ~/vigimeteo-db-data`.  
+It persists data even after the application is stopped.
+
+---
+
+## 5. Container configuration
+
+### Backend – environment variables
+
+The backend connects to the database using these environment variables set in `deployment.yaml`:
+
+| Variable | Value |
+|---|---|
+| `DB_HOST` | `vigimeteo-db.vigimeteo.svc.cluster.local` |
+| `DB_PORT` | `5432` |
+| `DB_NAME` | `postgres` |
+| `DB_USER` | `postgres` |
+| `DB_PASSWORD` | `admin` |
+
+### Backend – init container
+
+To avoid connection errors on startup, a `busybox` init container runs first and waits until PostgreSQL accepts connections on port 5432:
+
+```bash
+until nc -z vigimeteo-db.vigimeteo.svc.cluster.local 5432; do sleep 3; done
+```
+
+### Database – init script
+
+The ConfigMap `vigimeteo-db-init` contains `init.sql` and is mounted into `/docker-entrypoint-initdb.d/` inside the PostgreSQL container. PostgreSQL automatically runs all `.sql` files in that folder on first startup.
+
+### Images
+
+Both images are built locally with `imagePullPolicy: IfNotPresent` so Kubernetes never tries to pull them from a registry.
+
+---
+
+## 6. How to run the application
+
+### Prerequisites
+- `docker` installed and running
+- `kubectl` configured and connected to a cluster
+- For **Minikube**: run `eval $(minikube docker-env)` first so images are built inside Minikube's daemon
+
+### Step 1 – Prepare (first time only)
+
+```bash
+bash prepare-app.sh
+```
+
+This creates the PV host directory and builds the two Docker images.
+
+### Step 2 – Start
+
+```bash
+bash start-app.sh
+```
+
+Applies all Kubernetes objects in the correct order and waits for PostgreSQL to be ready before deploying the backend.
+
+### Step 3 – Pause / restart
+
+There is no "pause" in Kubernetes. To stop traffic you can scale down replicas:
+
+```bash
+kubectl scale deployment vigimeteo-backend vigimeteo-frontend --replicas=0 -n vigimeteo
+```
+
+To restart:
+
+```bash
+kubectl scale deployment vigimeteo-backend vigimeteo-frontend --replicas=2 -n vigimeteo
+```
+
+### Step 4 – Delete
+
+```bash
+bash stop-app.sh
+```
+
+This deletes the namespace (which removes all objects inside it) and the PersistentVolume.  
+The data folder `~/vigimeteo-db-data` is **not** deleted. To fully clean up:
+
+```bash
+rm -rf ~/vigimeteo-db-data
+```
+
+---
+
+## 7. How to access the application
+
+Once the app is started, open your browser at:
+
+**http://localhost:30500**
+
+### Test credentials
+
+| Role | Email | Password |
+|---|---|---|
+| Admin | `admin@a.com` | `azertyuiop` |
+| Complexe user | `complexe@gmail.com` | `azertyuiop` |
+| Regular user | `user@gmail.com` | `azertyuiop` |
+
+### Verify everything is running
+
+```bash
+kubectl get all -n vigimeteo
+```
+
+All pods should show `1/1 Running`.
+
+---
+
+## Troubleshooting
+
+**Pod stays `Pending`** → The PVC is not bound. Run `kubectl describe pod -n vigimeteo <pod-name>` and check the events. Make sure `~/vigimeteo-db-data` exists.
+
+**Backend `CrashLoopBackOff`** → Check logs with `kubectl logs -n vigimeteo deployment/vigimeteo-backend`. Usually a DB connection issue.
+
+**Images not found** → For Minikube, run `eval $(minikube docker-env)` before `prepare-app.sh`.