# MariaDB HA Demo

Real-time high availability demonstration with a 6-node MariaDB cluster, MaxScale proxy, and live dashboard.

---

## Quick Start

```bash
git clone https://git.sechpoint.app/customer-engineering/mariadb-demo.git
cd mariadb-demo
bash deploy.sh
```

Open **http://{host}:5000** in your browser.

---

## Architecture

```
┌─ Cluster 1 ─────────────┐    ┌─ Cluster 2 ─────────────┐
│ mariadb1  PRIMARY       │    │ mariadb4  SECONDARY      │
│ mariadb2  SECONDARY     │    │ mariadb5  SECONDARY      │
│ mariadb3  SECONDARY     │    │ mariadb6  SECONDARY      │
└─────────────────────────┘    └──────────────────────────┘
              │                           │
              └─────── MaxScale ──────────┘
                     (port 4000)
                          │
                   ┌──────┴──────┐
                   │  Dashboard  │
                   │  (port 5000)│
                   └─────────────┘
```

- **6 MariaDB nodes**: 2 clusters with GTID-based async replication
- **MaxScale 24.02**: read-write splitting, automatic failover
- **Dashboard**: real-time SSE transaction monitor with per-server toggle controls

---

## Dashboard Controls

| Action | How |
|--------|-----|
| Start transactions | Click **⚡ Initialize DB** then **▶ Start Demo** |
| Kill a server | Click the green/red circle on any server card |
| Kill entire cluster | Toggle all 3 servers in a cluster OFF |
| Recover | Click the circle again (red → green) |
| Switch mode | Use dropdown: **Primary + DR** or **2 Independent Clusters** |

### What Visitors See
- **Terminal feed**: live INSERT→SELECT→DELETE transactions
- **Status circle**: green = healthy, red = transaction lost
- **Server cards**: PRIMARY (green), SECONDARY (blue), DOWN (red)
- **Availability %**: drops during failover, recovers automatically

---

## Demo Scenarios

### 1. Standard Failover
Kill the PRIMARY server — MaxScale promotes a SECONDARY. Availability drops briefly, then recovers.

### 2. Cross-Cluster Failover (DR Mode)
Switch to **Primary + DR** mode. Kill all 3 servers in Cluster 1 — Cluster 2 takes over as PRIMARY.

### 3. Independent Clusters
Switch to **2 Independent Clusters**. Each cluster has its own PRIMARY — kill one without affecting the other.

### 4. MaxScale GUI
Open **http://{host}:5000/maxscale** — full MaxScale admin interface. Login: `admin` / `mariadb`

---

## Systemd Services

```bash
sudo systemctl start mariadb-cluster    # Start cluster
sudo systemctl stop mariadb-cluster     # Stop everything
sudo systemctl start mariadb-monitor    # Start dashboard
bash scripts/cluster.sh status          # Health check
```

Services auto-start on boot when installed via `deploy.sh`.

---

## Requirements

- Ubuntu 24.04+ / Debian 12+
- 8 GB RAM, 4 CPU cores
- Docker installed (`deploy.sh` handles this automatically)
- Ports: 5000 (dashboard), 4000 (MaxScale), 8989 (MaxScale API), 3307–3312 (MariaDB)

---

## Manual Deployment (without deploy.sh)

```bash
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt

# Start cluster
bash scripts/cluster.sh start

# Start dashboard
python3 app.py
```

---

## Files

| File | Purpose |
|------|---------|
| `engine.py` | Transaction engine (INSERT→SELECT→DELETE every 1s) |
| `app.py` | Flask app: routes, SSE endpoint, MaxScale proxy |
| `scripts/cluster.sh` | Docker cluster control (start/stop/status) |
| `scripts/mariadb-cluster.service` | Systemd unit for cluster |
| `scripts/mariadb-monitor.service` | Systemd unit for dashboard |
| `cluster-config/` | MariaDB config files (server1-6.cnf) |
| `templates/dashboard.html` | Single-page dashboard |
| `static/dashboard.js` | Dashboard logic + SSE consumer |
| `static/dashboard.css` | Dark theme styles |
| `deploy.sh` | One-command deployment |
| `requirements.txt` | Python dependencies |