openova/platform/vllm

vLLM

High-performance LLM inference engine with PagedAttention.

Status: Accepted | Updated: 2026-02-07

---

Overview

vLLM provides high-throughput LLM serving with efficient memory management via PagedAttention. Recommended runtime for LLM inference in OpenOva.

flowchart LR
    subgraph vLLM["vLLM Engine"]
        PagedAttn[PagedAttention]
        Scheduler[Continuous Batching]
        KVCache[KV Cache Management]
    end

    subgraph API["OpenAI-Compatible API"]
        Chat[/v1/chat/completions]
        Completions[/v1/completions]
        Models[/v1/models]
    end

    Request[Request] --> API
    API --> vLLM
    vLLM --> GPU[GPU]

---

Why vLLM?

Feature	Benefit
PagedAttention	24x higher throughput than HuggingFace
Continuous batching	Efficient request handling
OpenAI-compatible API	Drop-in replacement
Tensor parallelism	Multi-GPU support
Quantization	AWQ, GPTQ, INT8 support

---

Supported Models

Model Family	Examples
Qwen	Qwen2.5, Qwen3 (recommended)
Llama	Llama 3.1, Llama 3.2
Mistral	Mistral, Mixtral
DeepSeek	DeepSeek-R1, DeepSeek-V3
Others	Phi, Gemma, Yi, etc.

---

Configuration

Deployment via KServe

apiVersion: serving.kserve.io/v1beta1
kind: InferenceService
metadata:
  name: qwen-32b
  namespace: ai-hub
spec:
  predictor:
    model:
      modelFormat:
        name: vllm
      runtime: vllm-runtime
      storageUri: pvc://model-cache/models/qwen3-32b-awq
    resources:
      requests:
        nvidia.com/gpu: "2"
      limits:
        nvidia.com/gpu: "2"

Standalone Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: vllm
  namespace: ai-hub
spec:
  replicas: 1
  selector:
    matchLabels:
      app: vllm
  template:
    spec:
      containers:
        - name: vllm
          image: vllm/vllm-openai:latest
          args:
            - --model=/models/qwen3-32b-awq
            - --tensor-parallel-size=2
            - --max-model-len=32768
            - --gpu-memory-utilization=0.9
            - --enable-prefix-caching
          ports:
            - containerPort: 8000
          resources:
            requests:
              nvidia.com/gpu: "2"
            limits:
              nvidia.com/gpu: "2"
          volumeMounts:
            - name: model-cache
              mountPath: /models
      volumes:
        - name: model-cache
          persistentVolumeClaim:
            claimName: model-cache

---

Key Parameters

Parameter	Purpose	Example
--model	Model path or HuggingFace ID	/models/qwen3-32b
--tensor-parallel-size	Number of GPUs	2
--max-model-len	Maximum context length	32768
--gpu-memory-utilization	GPU memory fraction	0.9
--quantization	Quantization method	awq, gptq
--enable-prefix-caching	Cache common prefixes	-

---

API Usage

Chat Completions

curl http://vllm.ai-hub.svc:8000/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "qwen3-32b",
    "messages": [
      {"role": "user", "content": "Hello!"}
    ],
    "stream": true
  }'

With Thinking Mode (Qwen3)

curl http://vllm.ai-hub.svc:8000/v1/chat/completions \
  -d '{
    "model": "qwen3-32b",
    "messages": [
      {"role": "user", "content": "Solve this step by step: ..."}
    ],
    "extra_body": {
      "chat_template_kwargs": {"enable_thinking": true}
    }
  }'

---

Multi-GPU Configuration

Tensor Parallelism (Single Node)

args:
  - --tensor-parallel-size=4  # Split model across 4 GPUs

Pipeline Parallelism (Multi-Node)

args:
  - --pipeline-parallel-size=2  # Split across 2 nodes
  - --tensor-parallel-size=4    # 4 GPUs per node

---

Quantization

Method	Memory Reduction	Quality
AWQ	~4x	Excellent
GPTQ	~4x	Good
INT8	~2x	Very Good
FP8	~2x	Excellent

args:
  - --quantization=awq
  - --dtype=half

---

Monitoring

Metric	Query
Request latency	vllm:request_latency_seconds
Tokens/second	vllm:generation_tokens_total
GPU memory	vllm:gpu_cache_usage_perc
Queue length	vllm:num_requests_waiting

---

Consequences

Positive:

• Industry-leading performance
• OpenAI-compatible API
• Excellent quantization support
• Multi-GPU scaling
• Active development

Negative:

• GPU required
• Memory-intensive for large models
• Some models not yet supported

---

Part of OpenOva