# HAProxy Dynamic Load Balancer Management Suite

Runtime management of HAProxy without restarts. Provides an MCP (Model Context Protocol) interface for dynamic domain/server management with zero-reload operations.

## Key Features

- **Zero-reload domain management** using HAProxy map files and pool backends
- **Dynamic server management** with auto-persistence
- **SSL/TLS certificate management** with zero-downtime deployment via Runtime API
- **Pool sharing** for multiple domains pointing to the same backend
- **HTTP/3 (QUIC)** support alongside HTTP/1.1 and HTTP/2
- **29 MCP tools** across domain, server, health, monitoring, config, and certificate management
- **IPv4 and IPv6** support

## Architecture

```
┌──────────────────────────────────────────────────┐
│ HAProxy (host network)                           │
│ TCP 80/443 (HTTP/1.1, HTTP/2) + UDP 443 (HTTP/3) │
│ Runtime API: localhost:9999                      │
│ MCP Proxy: mcp.inouter.com → localhost:8000      │
└──────────────┬───────────────────────────────────┘
               │
         ┌─────▼─────┐
         │ MCP       │
         │ Server    │
         │ :8000     │
         └───────────┘
```

### Domain Routing Flow

```
Request → HAProxy Frontend
    ↓
domains.map lookup (Host header)
    ↓
pool_N backend (N = 1-100)
    ↓
Server (from servers.json, auto-restored on startup)
```

### Pool-Based Routing

- Domains map to pools: `example.com` → `pool_N`
- 100 pools available: `pool_1` to `pool_100`
- Each pool has 10 server slots (`pool_N_1` to `pool_N_10`)

## Prerequisites

- **HAProxy 3.x** (running as Podman Quadlet container)
- **Python 3.11+**
- **uv** (Python package manager)
- **acme.sh** (for SSL certificate management)
- **Cloudflare** DNS (for DNS-01 ACME challenges)

## Installation

1. Clone the repository to `/opt/haproxy/`

2. Install dependencies:
   ```bash
   cd /opt/haproxy/haproxy_mcp
   uv sync
   ```

3. Start HAProxy:
   ```bash
   systemctl start haproxy
   ```

4. Start the MCP server:
   ```bash
   systemctl start haproxy-mcp
   ```

## Services

### HAProxy (Podman Quadlet)

```bash
systemctl start haproxy      # Start
systemctl stop haproxy       # Stop
systemctl restart haproxy    # Restart
systemctl status haproxy     # Status
```

- Quadlet config: `/etc/containers/systemd/haproxy.container`
- Network mode: `host`

### MCP Server (systemd)

```bash
systemctl start haproxy-mcp     # Start
systemctl stop haproxy-mcp      # Stop
systemctl restart haproxy-mcp   # Restart
journalctl -u haproxy-mcp -f    # Logs
```

- Transport: `streamable-http`
- Internal: `http://localhost:8000/mcp`
- External: `https://mcp.inouter.com/mcp` (via HAProxy)

### Environment Variables

| Variable | Default | Description |
|----------|---------|-------------|
| `MCP_HOST` | `0.0.0.0` | MCP server bind host |
| `MCP_PORT` | `8000` | MCP server port |
| `HAPROXY_HOST` | `localhost` | HAProxy Runtime API host |
| `HAPROXY_PORT` | `9999` | HAProxy Runtime API port |
| `HAPROXY_STATE_FILE` | `/opt/haproxy/data/servers.state` | State file path |
| `HAPROXY_MAP_FILE` | `/opt/haproxy/conf/domains.map` | Map file path |
| `HAPROXY_SERVERS_FILE` | `/opt/haproxy/conf/servers.json` | Servers config path |
| `HAPROXY_POOL_COUNT` | `100` | Number of pool backends |
| `HAPROXY_MAX_SLOTS` | `10` | Max servers per pool |
| `HAPROXY_CONTAINER` | `haproxy` | Podman container name |
| `LOG_LEVEL` | `INFO` | Logging level (DEBUG/INFO/WARNING/ERROR) |

## Usage

### Zero-Reload Domain Management

#### Adding a Domain

```python
haproxy_add_domain("example.com", ip="10.0.0.1")
# Creates: pool_N_1 → 10.0.0.1:80

haproxy_add_domain("api.example.com", ip="10.0.0.1", http_port=8080)
# Creates: pool_N_1 → 10.0.0.1:8080
```

This will:
1. Find an available pool (e.g., `pool_5`)
2. Add to `domains.map`: `example.com pool_5`
3. Update HAProxy runtime map via Runtime API
4. Configure server in pool (HTTP only)
5. Save to `servers.json` for persistence

**No HAProxy reload required!**

#### Pool Sharing

Multiple domains can share the same pool/backend servers:

```python
# First domain gets its own pool
haproxy_add_domain("example.com", ip="10.0.0.1")
# Creates: example.com → pool_5

# Additional domains share the same pool
haproxy_add_domain("www.example.com", share_with="example.com")
haproxy_add_domain("api.example.com", share_with="example.com")
# Both use: pool_5 (same backend servers)
```

Benefits:
- Saves pool slots (100 pools can serve unlimited domains)
- Multiple domains share the same backend servers
- Removing a shared domain keeps servers intact

#### Bulk Server Operations

```python
haproxy_add_servers("api.example.com", '[
  {"slot": 1, "ip": "10.0.0.1", "http_port": 80},
  {"slot": 2, "ip": "10.0.0.2", "http_port": 80},
  {"slot": 3, "ip": "2001:db8::1", "http_port": 80}
]')
```

### SSL/TLS Certificates

Certificates are managed via acme.sh with Cloudflare DNS validation and deployed to HAProxy with zero downtime using the Runtime API.

| Item | Value |
|------|-------|
| ACME Client | acme.sh (Google Trust Services CA) |
| Cert Directory | `/opt/haproxy/certs/` |
| DNS Validation | Cloudflare |

```python
# Issue a new certificate (with wildcard)
haproxy_issue_cert("example.com", wildcard=True)

# Renew a certificate
haproxy_renew_cert("example.com")

# List all certificates
haproxy_list_certs()
```

### Health Checks

```python
# System health
haproxy_health()
# Returns: {"status": "healthy", "components": {...}}

# Domain-specific health
haproxy_domain_health("api.example.com")
# Returns: {"status": "healthy", "servers": [...], "healthy_count": 1}
```

Status values: `healthy` (all UP), `degraded` (partial UP), `down` (all DOWN), `no_servers`

## MCP Tools (29 total)

### Domain Management

| Tool | Description |
|------|-------------|
| `haproxy_list_domains` | List domains (use `include_wildcards=true` for wildcards) |
| `haproxy_add_domain` | Add domain to pool (no reload), supports `share_with` for pool sharing |
| `haproxy_remove_domain` | Remove domain from pool (no reload) |

### Server Management

| Tool | Description |
|------|-------------|
| `haproxy_list_servers` | List servers for a domain |
| `haproxy_add_server` | Add server to slot (1-10 or 0=auto), auto-saved |
| `haproxy_add_servers` | Bulk add servers (JSON array), auto-saved |
| `haproxy_remove_server` | Remove server from slot, auto-saved |
| `haproxy_set_server_state` | Set state: ready/drain/maint |
| `haproxy_set_server_weight` | Set weight (0-256) |
| `haproxy_set_domain_state` | Set all servers of domain to ready/drain/maint |
| `haproxy_wait_drain` | Wait for connections to drain (timeout configurable) |

### Health Check

| Tool | Description |
|------|-------------|
| `haproxy_health` | System health (MCP, HAProxy, config files) |
| `haproxy_domain_health` | Domain-specific health with server status |
| `haproxy_get_server_health` | Get UP/DOWN/MAINT status for all servers |

### Monitoring

| Tool | Description |
|------|-------------|
| `haproxy_stats` | HAProxy statistics |
| `haproxy_backends` | List backends |
| `haproxy_list_frontends` | List frontends with status |
| `haproxy_get_connections` | Active connections per server |

### Configuration

| Tool | Description |
|------|-------------|
| `haproxy_reload` | Validate, reload config, auto-restore servers |
| `haproxy_check_config` | Validate config syntax |
| `haproxy_save_state` | Save server state to disk |
| `haproxy_restore_state` | Restore state from disk |

### Certificate Management (Zero-Downtime)

| Tool | Description |
|------|-------------|
| `haproxy_list_certs` | List all certificates with expiry info |
| `haproxy_cert_info` | Get detailed certificate info (expiry, issuer, SANs) |
| `haproxy_issue_cert` | Issue new certificate via acme.sh + Cloudflare DNS |
| `haproxy_renew_cert` | Renew specific certificate (force option available) |
| `haproxy_renew_all_certs` | Renew all certificates due for renewal |
| `haproxy_delete_cert` | Delete certificate from acme.sh and HAProxy |
| `haproxy_load_cert` | Load/reload certificate into HAProxy (manual trigger) |

## MCP Connection

**Tailscale (no auth):**
```bash
claude mcp add --transport http haproxy http://100.108.39.107:8000/mcp
```

**External (with auth):**
```bash
curl -X POST https://mcp.inouter.com/mcp \
  -H "Authorization: Bearer <token>" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}},"id":0}'
```

Access rules:
| Source | Token Required |
|--------|----------------|
| Tailscale (100.64.0.0/10) | No |
| External | Yes |

Token location: `/opt/haproxy/conf/mcp-token.env`

## Safety Features

- **Atomic file writes**: Temp file + rename prevents corruption
- **File locking**: Prevents race conditions on concurrent operations
- **Disk-first pattern**: Config saved before HAProxy update, rollback on failure
- **Command validation**: HAProxy responses checked for errors
- **Input validation**: Domain format, IP (v4/v6), port range, slot limits
- **Bulk limits**: Max 10 servers per bulk add, 10KB JSON size limit
- **Command batching**: Multiple HAProxy commands sent in single TCP connection

## Directory Structure

```
/opt/haproxy/
├── haproxy_mcp/         # MCP server package (streamable-http)
│   ├── server.py        # Main entry point
│   ├── config.py        # Configuration and constants
│   ├── exceptions.py    # Exception classes
│   ├── validation.py    # Input validation
│   ├── haproxy_client.py # HAProxy Runtime API client
│   ├── file_ops.py      # File I/O operations
│   ├── utils.py         # Parsing utilities
│   └── tools/           # MCP tools (29 total)
│       ├── domains.py   # Domain management (3 tools)
│       ├── servers.py   # Server management (7 tools)
│       ├── health.py    # Health checks (3 tools)
│       ├── monitoring.py # Monitoring (4 tools)
│       ├── configuration.py # Config management (4 tools)
│       └── certificates.py # Certificate management (7 tools)
├── conf/
│   ├── haproxy.cfg      # Main HAProxy config (100 pool backends)
│   ├── domains.map      # Domain → Pool mapping
│   ├── servers.json     # Server persistence (auto-managed)
│   ├── certificates.json # Certificate domain list (auto-managed)
│   └── mcp-token.env    # Bearer token for MCP auth
├── certs/               # SSL/TLS certificates (HAProxy PEM format)
├── data/                # Legacy state files
├── scripts/             # Utility scripts
└── run/                 # Runtime socket files
```

## Startup Sequence

```
1. systemd starts haproxy.service
   ↓
2. HAProxy loads haproxy.cfg (100 pool backends)
   ↓
3. HAProxy loads domains.map (domain → pool mapping)
   ↓
4. systemd starts haproxy-mcp.service
   ↓
5. MCP server reads servers.json & certificates.json
   ↓
6. MCP server restores servers via Runtime API
   ↓
7. MCP server loads certificates via Runtime API (zero-downtime)
   ↓
8. Ready to serve traffic
```

## HAProxy Runtime API

```bash
# Show domain mappings
echo "show map /usr/local/etc/haproxy/domains.map" | nc localhost 9999

# Add domain mapping
echo "add map /usr/local/etc/haproxy/domains.map example.com pool_5" | nc localhost 9999

# Show server state
echo "show servers state" | nc localhost 9999

# Set server address
echo "set server pool_1/pool_1_1 addr 10.0.0.1 port 80" | nc localhost 9999

# Enable server
echo "set server pool_1/pool_1_1 state ready" | nc localhost 9999
```

## License

MIT