KVM MCP Server

A powerful JSON-RPC server for managing KVM virtual machines through a simple and intuitive interface. This server provides a centralized way to control and monitor your KVM virtual machines using a standardized protocol.

Why This Project?

Managing KVM virtual machines typically requires using multiple command-line tools like virsh, virt-install, and qemu-system. This project aims to:

1. Simplify VM Management: Provide a single, unified interface for all VM operations
2. Enable Remote Control: Allow remote management of VMs through JSON-RPC
3. Automate VM Operations: Make it easy to script and automate VM management tasks
4. Standardize VM Configuration: Ensure consistent VM setup across your infrastructure
5. Optimize Performance: Implement efficient resource management and caching strategies

Features

- VM Lifecycle Management:
- Create new VMs with customizable parameters
- Start/stop/reboot VMs
- List all available VMs with their status
- Automatic state tracking and recovery

- Network Management:
- Configure VM networking using bridges
- Support for the brforvms bridge
- Automatic network interface configuration
- IP address tracking and management

- Storage Management:
- Configurable VM disk storage location
- Support for various disk formats (qcow2)
- Configurable disk sizes
- Automatic disk cleanup and management

- Display Management:
- VNC support for graphical access
- Automatic VNC port assignment
- Tools to find and connect to VM displays
- Display state tracking and recovery

- Installation Support:
- Network installation from ISO images
- Local installation from CDROM
- Support for various OS variants
- Automated installation configuration

- Performance Optimizations:
- Connection pooling for libvirt to reduce connection overhead
- VM information caching for improved responsiveness
- Asynchronous processing for better concurrency
- Advanced logging for diagnostics and troubleshooting
- Graceful shutdown handling for proper resource cleanup
- Automatic connection recovery and validation
- Rate limiting for API operations
- Performance metrics collection

Performance Benefits

Connection Pooling

- Reduced Latency: Eliminates the overhead of repeatedly opening and closing libvirt connections - Resource Efficiency: Maintains a pool of reusable connections, reducing system resource usage - Automatic Recovery: Detects and replaces dead connections automatically - Configurable Pool Size: Adjust the number of connections based on your workload

Caching

- Faster Response Times: Reduces repeated queries to libvirt for common operations - Configurable TTL: Set cache expiration based on your needs - Selective Bypass: Option to bypass cache for operations requiring fresh data - Automatic Invalidation: Cache is automatically invalidated when VM states change

Asynchronous Processing

- Improved Concurrency: Handle multiple requests simultaneously - Better Resource Utilization: Efficient use of system resources - Non-blocking Operations: Long-running operations don't block the server - Graceful Shutdown: Proper cleanup of resources during shutdown

Monitoring and Diagnostics

- Structured Logging: Easy-to-parse log format for analysis - Performance Metrics: Track operation timing and resource usage - Error Tracking: Detailed error logging for troubleshooting - Resource Monitoring: Track connection pool usage and cache effectiveness

Configuration

The server uses a JSON configuration file (config.json) to store default values and paths. This makes the server more portable and easier to customize. The configuration includes:

{
    "vm": {
        "disk_path": "/vm",                    // Base directory for VM disk storage
        "default_iso": "/iso/ubuntu-24.04.2-live-server-amd64.iso",  // Default installation media for Ubuntu-based VMs
        "default_master_image": "/iso/fedora-coreos-41-qemu.x86_64.qcow2",  // Default base image for Fedora CoreOS VMs
        "default_name": "newvmname",           // Default VM name
        "default_memory": 2048,                // Default memory allocation in MB
        "default_vcpus": 2,                    // Default number of virtual CPUs
        "default_disk_size": 20,               // Default disk size in GB
        "default_os_variant": "generic",       // Default OS variant for virt-install
        "default_network": "brforvms",         // Default network bridge for VM networking
        "ignition": {                          // Fedora CoreOS specific configuration
            "default_hostname": "coreos",      // Default hostname for CoreOS VMs
            "default_user": "core",            // Default user for CoreOS VMs
            "default_ssh_key": "~/.ssh/id_rsa.pub",  // Default SSH public key path
            "default_timezone": "UTC",         // Default timezone
            "default_locale": "en_US.UTF-8",   // Default system locale
            "default_password_hash": null      // Optional: Default password hash for user
        }
    }
}

You can modify these values to match your environment's requirements. The configuration supports environment variable overrides using the following format:
- VM_DISK_PATH for disk_path
- VM_DEFAULT_ISO for default_iso
- VM_DEFAULT_MASTER_IMAGE for default_master_image
- VM_DEFAULT_NAME for default_name
- VM_DEFAULT_MEMORY for default_memory
- VM_DEFAULT_VCPUS for default_vcpus
- VM_DEFAULT_DISK_SIZE for default_disk_size
- VM_DEFAULT_OS_VARIANT for default_os_variant
- VM_DEFAULT_NETWORK for default_network
- VM_IGNITION_DEFAULT_HOSTNAME for ignition.default_hostname
- VM_IGNITION_DEFAULT_USER for ignition.default_user
- VM_IGNITION_DEFAULT_SSH_KEY for ignition.default_ssh_key
- VM_IGNITION_DEFAULT_TIMEZONE for ignition.default_timezone
- VM_IGNITION_DEFAULT_LOCALE for ignition.default_locale
- VM_IGNITION_DEFAULT_PASSWORD_HASH for ignition.default_password_hash

Performance Tuning

Connection Pool Configuration

connection_pool = LibvirtConnectionPool(
    max_connections=5,     # Maximum number of connections in the pool
    timeout=30,            # Timeout for getting a connection (seconds)
    uri='qemu:///system'   # Libvirt connection URI
)

Cache Configuration

vm_info_cache = VMInfoCache(
    max_size=50,           # Maximum number of VMs to cache
    ttl=60                 # Time-to-live for cache entries (seconds)
)

Logging Configuration

logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
    handlers=[
        RotatingFileHandler(
            'kvm_mcp.log',
            maxBytes=10485760,  # 10MB
            backupCount=5
        ),
        logging.StreamHandler()
    ]
)

Getting Started

Prerequisites

- Python 3.6 or higher
- KVM and libvirt installed on the host system
- The network bridge configured (default: brforvms)
- VM storage directory created (default: /vm/)
- Sufficient system resources for your VM workload

Installation

1. Clone this repository:

   git clone https://github.com/yourusername/kvm-mcp.git

   cd kvm-mcp

   

2. Create and activate a virtual environment:

   python3 -m venv .venv

   source .venv/bin/activate

   

3. Install dependencies:

   pip install -r requirements.txt

   

4. Configure the server:
- Edit config.json to match your environment
- Ensure all required directories exist
- Verify network bridge configuration
- Adjust performance settings as needed

Usage

1. Start the server:

   python3 kvm_mcp_server.py

   

2. Send commands using JSON-RPC. Example scripts are provided:
- create_vm.sh: Create a new VM using default configuration
- get_vnc_ports.sh: Find VNC ports for running VMs

Example Commands

Create a New VM

./create_vm.sh

This will create a new VM using the default configuration from config.json. You can override any of these defaults by providing them in the request.

Find VNC Ports

./get_vnc_ports.sh

This will show all running VMs and their VNC ports, making it easy to connect to their displays.

List VMs with Cache Bypass

echo '{"jsonrpc": "2.0", "method": "tools/call", "params": {"name": "list_vms", "arguments": {"no_cache": true}}, "id": 1}' | python3 kvm_mcp_server.py

Monitoring and Troubleshooting

Log Files

- kvm_mcp.log: Current log file - kvm_mcp.log.1: Previous log file (rotated) - Logs include timing information, connection pool status, and cache hits/misses

Performance Metrics

- Connection pool usage statistics - Cache hit/miss ratios - Operation timing metrics - Resource utilization statistics

Common Issues and Solutions

1. Connection Pool Exhaustion
- Symptom: Slow response times or connection errors
- Solution: Increase max_connections in the connection pool configuration

2. Cache Invalidation Issues
- Symptom: Stale VM information
- Solution: Use no_cache parameter or reduce cache TTL

3. Resource Cleanup
- Symptom: Resource leaks or connection issues
- Solution: Ensure proper shutdown using SIGTERM or SIGINT

Project Structure

- kvm_mcp_server.py: Main server implementation
- config.json: Configuration file
- requirements.txt: Python dependencies
- Example scripts in the root directory
- Test suite in the tests/ directory

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.