> ## Documentation Index
> Fetch the complete documentation index at: https://infercrane.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# vLLM

> How InferCrane manages and routes requests to vLLM runtimes.

# vLLM

vLLM is InferCrane's default qualified runtime profile. InferCrane owns deployment state and
lifecycle; vLLM owns model execution. A supervised [vLLM Router](https://github.com/vllm-project/semantic-router)
process distributes requests across healthy standalone replicas.

## Connect existing workers

Each worker must expose the OpenAI-compatible vLLM API and be reachable from the InferCrane gateway.

```bash theme={"theme":{"light":"github-light-default","dark":"vesper"}}
infercrane target add gpu-a \
  --url http://gpu-a:8000 \
  --runtime vllm \
  --upstream-model Qwen/Qwen3-8B

infercrane apply Qwen/Qwen3-8B \
  --name qwen-prod \
  --targets gpu-a \
  --idempotency-key qwen-prod-initial \
  --wait
```

The reconciler verifies health and served-model identity before publishing a route. An unhealthy or mismatched worker does not enter the request path.

## Responsibility boundary

| InferCrane                            | vLLM                          |
| ------------------------------------- | ----------------------------- |
| Desired and observed deployment state | Model loading and execution   |
| Durable operations and revisions      | OpenAI-compatible worker API  |
| Health/model reconciliation           | Token generation and KV cache |
| Safe routing generations              | Per-replica runtime metrics   |

InferCrane does not implement an inference engine or distributed KV cache. SGLang and custom OCI
workloads use the same versioned runtime boundary and have independent qualification states.

<Card title="Gateway and routing" icon="route" href="/features/gateway">
  Follow an OpenAI request from alias resolution to a healthy vLLM replica.
</Card>
