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