hpc-as-api 0.1.0

OpenAI-compatible API gateway for HPC clusters via Globus Compute

hpc-as-api

OpenAI-compatible API gateway for HPC clusters via Globus Compute.

hpc-as-api exposes any vLLM-served model running on an HPC cluster (SLURM, PBS, etc.) as a standard OpenAI-compatible REST API. It handles authentication, rate limiting, payload size management, and real-time token streaming — so your existing OpenAI clients work without modification.

from hpc_as_api.compute import GlobusComputeClient

client = GlobusComputeClient(
    endpoint_id="8d978809-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
    models={
        "qwen25-vl-72b": {
            "hf_name": "Qwen/Qwen2.5-VL-72B-Instruct-AWQ",
            "url": "http://ghi2-002:8000",
            "context_reserve_output": 4096,
        }
    },
)
result = await client.submit_inference(
    messages=[{"role": "user", "content": "Explain quantum entanglement."}],
    model="qwen25-vl-72b",
)

Why

HPC clusters run the largest open-source LLMs (72B+ parameters) on GPU hardware that typical cloud users can't afford. But HPC infrastructure has no standard API surface — each cluster has its own SLURM scripts, SSH tunnels, and authentication systems. hpc-as-api provides a uniform OpenAI-compatible interface over any vLLM-served model, using Globus Compute for authentication and job dispatch (no open ports required on the HPC side).

Architecture

Your App / OpenAI Client
        │  POST /v1/chat/completions
        ▼
  hpc-as-api (FastAPI)
        │  Globus Compute (AMQP — no HPC firewall holes)
        ▼
  HPC Cluster (SLURM)
        │  vLLM HTTP API (internal LAN)
        ▼
  GPU Compute Node
        │  tokens flow via WebSocket relay (streamrelay)
        ▼
  hpc-as-api → SSE stream → Your App

Key design points:

• No open ports on HPC: Globus Compute is outbound-only from the cluster
• Real-time streaming: Tokens stream back via streamrelay WebSocket relay
• E2E encryption: Optional AES-256-GCM encryption between HPC and consumer (relay sees only ciphertext)
• OpenAI-compatible: Drop-in for any client using the OpenAI SDK

Installation

# Base package (no Globus SDK)
pip install hpc-as-api

# With Globus Compute support
pip install "hpc-as-api[globus]"

Quickstart: Run as a service

Set environment variables and start:

export GLOBUS_COMPUTE_ENDPOINT_ID="your-endpoint-uuid"
export HPC_MODELS='{"qwen25-vl-72b": {"hf_name": "Qwen/Qwen2.5-VL-72B-Instruct-AWQ", "url": "http://ghi2-002:8000", "context_reserve_output": 4096}}'
export RELAY_URL="wss://relay.example.com"
export RELAY_SECRET="your-relay-secret"

uvicorn hpc_as_api.app:app --host 0.0.0.0 --port 8001

The gateway is now reachable at http://localhost:8001/v1/chat/completions with the standard OpenAI API schema.

Embed in an existing FastAPI app

from fastapi import FastAPI
from hpc_as_api.app import router

app = FastAPI()
app.include_router(router, prefix="/hpc")

Configuration reference

Variable	Default	Description
GLOBUS_COMPUTE_ENDPOINT_ID	—	Globus endpoint UUID for the HPC cluster
HPC_MODELS	{}	JSON dict: model name → HPC config
RELAY_URL	—	WebSocket relay URL for token streaming
RELAY_SECRET	—	Shared secret for relay auth
RELAY_ENCRYPTION_KEY	—	AES-256 hex key for E2E encryption
USE_GLOBUS_COMPUTE	true	false to route directly via SSH tunnel
LAKESHORE_VLLM_ENDPOINT	http://localhost:8000	Direct vLLM URL (SSH mode)
HPC_PROXY_HOST	0.0.0.0	Bind host
HPC_PROXY_PORT	8001	Bind port

HPC_MODELS schema

{
  "my-model-name": {
    "hf_name": "org/ModelName",
    "url": "http://compute-node:8000",
    "context_reserve_output": 4096
  }
}

Authentication

The gateway supports two auth modes (configured in hpc_as_api/auth.py):

• Globus token: Bearer token from Globus Auth, validated via introspection
• API key: Static key from HPC_API_KEYS env var (comma-separated)

Development

git clone https://github.com/uicacer/hpc-as-api
cd hpc-as-api
uv sync --extra dev
uv run pytest

Related

• streamrelay — WebSocket relay for real-time token streaming from Globus Compute
• STREAM — Full tiered LLM routing system that uses hpc-as-api

License

Apache 2.0 — see LICENSE.

Citation

If you use hpc-as-api in research, please cite:

@software{nassar2025hpcgateway,
  author = {Nassar, Anas},
  title  = {hpc-as-api: OpenAI-compatible API gateway for HPC clusters via Globus Compute},
  year   = {2025},
  url    = {https://github.com/uicacer/hpc-as-api}
}