vllm/docs/source/deployment/security.md

Security Guide

Inter-Node Communication

All communications between nodes in a multi-node vLLM deployment are insecure by default and must be protected by placing the nodes on an isolated network. This includes:

1. PyTorch Distributed communications
2. KV cache transfer communications
3. Tensor, Pipeline, and Data parallel communications

Configuration Options for Inter-Node Communications

The following options control inter-node communications in vLLM:

1. Environment Variables:

   • VLLM_HOST_IP: Sets the IP address for vLLM processes to communicate on

2. KV Cache Transfer Configuration:

   • --kv-ip: The IP address for KV cache transfer communications (default: 127.0.0.1)
   • --kv-port: The port for KV cache transfer communications (default: 14579)

3. Data Parallel Configuration:

   • data_parallel_master_ip: IP of the data parallel master (default: 127.0.0.1)
   • data_parallel_master_port: Port of the data parallel master (default: 29500)

Notes on PyTorch Distributed

vLLM uses PyTorch's distributed features for some inter-node communication. For detailed information about PyTorch Distributed security considerations, please refer to the PyTorch Security Guide.

Key points from the PyTorch security guide:

• PyTorch Distributed features are intended for internal communication only
• They are not built for use in untrusted environments or networks
• No authorization protocol is included for performance reasons
• Messages are sent unencrypted
• Connections are accepted from anywhere without checks

Security Recommendations

1. Network Isolation:

   • Deploy vLLM nodes on a dedicated, isolated network
   • Use network segmentation to prevent unauthorized access
   • Implement appropriate firewall rules

2. Configuration Best Practices:

   • Always set VLLM_HOST_IP to a specific IP address rather than using defaults
   • Configure firewalls to only allow necessary ports between nodes

3. Access Control:

   • Restrict physical and network access to the deployment environment
   • Implement proper authentication and authorization for management interfaces
   • Follow the principle of least privilege for all system components

Reporting Security Vulnerabilities

If you believe you have found a security vulnerability in vLLM, please report it following the project's security policy. For more information on how to report security issues and the project's security policy, please see the vLLM Security Policy.