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SkyPilot

vLLM

vLLM 可以使用 SkyPilot 在云和 Kubernetes 上运行并扩展到多个服务副本，SkyPilot 是一个用于在任何云上运行 LLM 的开源框架。更多关于各种开放模型（如 Llama-3、Mixtral 等）的示例可以在 SkyPilot AI gallery 中找到。

前提条件

  • 前往 HuggingFace 模型页面 并请求访问模型 meta-llama/Meta-Llama-3-8B-Instruct。
  • 检查您已安装 SkyPilot（文档）。
  • 检查 sky check 是否显示云或 Kubernetes 已启用。
pip install skypilot-nightly
sky check

在单个实例上运行

请参阅用于服务的 vLLM SkyPilot YAML 文件，serving.yaml。

resources:
  accelerators: {L4, A10g, A10, L40, A40, A100, A100-80GB} # We can use cheaper accelerators for 8B model.
  use_spot: True
  disk_size: 512  # Ensure model checkpoints can fit.
  disk_tier: best
  ports: 8081  # Expose to internet traffic.

envs:
  MODEL_NAME: meta-llama/Meta-Llama-3-8B-Instruct
  HF_TOKEN: <your-huggingface-token>  # Change to your own huggingface token, or use --env to pass.

setup: |
  conda create -n vllm python=3.10 -y
  conda activate vllm

  pip install vllm==0.4.0.post1
  # Install Gradio for web UI.
  pip install gradio openai
  pip install flash-attn==2.5.7

run: |
  conda activate vllm
  echo 'Starting vllm api server...'
  python -u -m vllm.entrypoints.openai.api_server \
    --port 8081 \
    --model $MODEL_NAME \
    --trust-remote-code \
    --tensor-parallel-size $SKYPILOT_NUM_GPUS_PER_NODE \
    2>&1 | tee api_server.log &

  echo 'Waiting for vllm api server to start...'
  while ! `cat api_server.log | grep -q 'Uvicorn running on'`; do sleep 1; done

  echo 'Starting gradio server...'
  git clone https://github.com/vllm-project/vllm.git || true
  python vllm/examples/online_serving/gradio_openai_chatbot_webserver.py \
    -m $MODEL_NAME \
    --port 8811 \
    --model-url http://localhost:8081/v1 \
    --stop-token-ids 128009,128001

在列出的任意备选 GPU（L4, A10g, ...）上开始提供 Llama-3 8B 模型服务。

HF_TOKEN="your-huggingface-token" sky launch serving.yaml --env HF_TOKEN

检查命令输出。会有一个可分享的 gradio 链接（如下面的最后一行所示）。在浏览器中打开它，使用 LLaMA 模型进行文本补全。

(task, pid=7431) Running on public URL: https://<gradio-hash>.gradio.live

可选：提供 70B 模型服务而非默认的 8B，并使用更多 GPU。

HF_TOKEN="your-huggingface-token" \
  sky launch serving.yaml \
  --gpus A100:8 \
  --env HF_TOKEN \
  --env MODEL_NAME=meta-llama/Meta-Llama-3-70B-Instruct

扩展到多个副本

SkyPilot 可以通过内置的自动扩缩、负载均衡和容错机制将服务扩展到多个服务副本。您可以通过向 YAML 文件添加 services 部分来实现。

service:
  replicas: 2
  # An actual request for readiness probe.
  readiness_probe:
    path: /v1/chat/completions
    post_data:
    model: $MODEL_NAME
    messages:
      - role: user
        content: Hello! What is your name?
  max_completion_tokens: 1
点击查看完整的 recipe YAML 
service:
  replicas: 2
  # An actual request for readiness probe.
  readiness_probe:
    path: /v1/chat/completions
    post_data:
      model: $MODEL_NAME
      messages:
        - role: user
          content: Hello! What is your name?
      max_completion_tokens: 1

resources:
  accelerators: {L4, A10g, A10, L40, A40, A100, A100-80GB} # We can use cheaper accelerators for 8B model.
  use_spot: True
  disk_size: 512  # Ensure model checkpoints can fit.
  disk_tier: best
  ports: 8081  # Expose to internet traffic.

envs:
  MODEL_NAME: meta-llama/Meta-Llama-3-8B-Instruct
  HF_TOKEN: <your-huggingface-token>  # Change to your own huggingface token, or use --env to pass.

setup: |
  conda create -n vllm python=3.10 -y
  conda activate vllm

  pip install vllm==0.4.0.post1
  # Install Gradio for web UI.
  pip install gradio openai
  pip install flash-attn==2.5.7

run: |
  conda activate vllm
  echo 'Starting vllm api server...'
  python -u -m vllm.entrypoints.openai.api_server \
    --port 8081 \
    --model $MODEL_NAME \
    --trust-remote-code \
    --tensor-parallel-size $SKYPILOT_NUM_GPUS_PER_NODE \
    2>&1 | tee api_server.log

在多个副本上开始提供 Llama-3 8B 模型服务。

HF_TOKEN="your-huggingface-token" \
  sky serve up -n vllm serving.yaml \
  --env HF_TOKEN

等待服务就绪

watch -n10 sky serve status vllm
示例输出 
Services
NAME  VERSION  UPTIME  STATUS  REPLICAS  ENDPOINT
vllm  1        35s     READY   2/2       xx.yy.zz.100:30001

Service Replicas
SERVICE_NAME  ID  VERSION  IP            LAUNCHED     RESOURCES                STATUS  REGION
vllm          1   1        xx.yy.zz.121  18 mins ago  1x GCP([Spot]{'L4': 1})  READY   us-east4
vllm          2   1        xx.yy.zz.245  18 mins ago  1x GCP([Spot]{'L4': 1})  READY   us-east4

服务就绪 (READY) 后，您可以找到服务的单个端点，并通过该端点访问服务。

ENDPOINT=$(sky serve status --endpoint 8081 vllm)
curl -L http://$ENDPOINT/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "meta-llama/Meta-Llama-3-8B-Instruct",
    "messages": [
    {
      "role": "system",
      "content": "You are a helpful assistant."
    },
    {
      "role": "user",
      "content": "Who are you?"
    }
    ],
    "stop_token_ids": [128009,  128001]
  }'

要启用自动扩缩，您可以将 service 中的 replicas 替换为以下配置。

service:
  replica_policy:
    min_replicas: 2
    max_replicas: 4
    target_qps_per_replica: 2

当每个副本的 QPS 超过 2 时，这将自动扩缩服务。

点击查看完整的 recipe YAML 
service:
  replica_policy:
    min_replicas: 2
    max_replicas: 4
    target_qps_per_replica: 2
  # An actual request for readiness probe.
  readiness_probe:
    path: /v1/chat/completions
    post_data:
      model: $MODEL_NAME
      messages:
        - role: user
          content: Hello! What is your name?
      max_completion_tokens: 1

resources:
  accelerators: {L4, A10g, A10, L40, A40, A100, A100-80GB} # We can use cheaper accelerators for 8B model.
  use_spot: True
  disk_size: 512  # Ensure model checkpoints can fit.
  disk_tier: best
  ports: 8081  # Expose to internet traffic.

envs:
  MODEL_NAME: meta-llama/Meta-Llama-3-8B-Instruct
  HF_TOKEN: <your-huggingface-token>  # Change to your own huggingface token, or use --env to pass.

setup: |
  conda create -n vllm python=3.10 -y
  conda activate vllm

  pip install vllm==0.4.0.post1
  # Install Gradio for web UI.
  pip install gradio openai
  pip install flash-attn==2.5.7

run: |
  conda activate vllm
  echo 'Starting vllm api server...'
  python -u -m vllm.entrypoints.openai.api_server \
    --port 8081 \
    --model $MODEL_NAME \
    --trust-remote-code \
    --tensor-parallel-size $SKYPILOT_NUM_GPUS_PER_NODE \
    2>&1 | tee api_server.log

使用新配置更新服务

HF_TOKEN="your-huggingface-token" sky serve update vllm serving.yaml --env HF_TOKEN

停止服务

sky serve down vllm

可选：将 GUI 连接到端点

也可以使用单独的 GUI 前端访问 Llama-3 服务，这样发送到 GUI 的用户请求将在副本之间进行负载均衡。

点击查看完整的 GUI YAML 
envs:
  MODEL_NAME: meta-llama/Meta-Llama-3-8B-Instruct
  ENDPOINT: x.x.x.x:3031 # Address of the API server running vllm.

resources:
  cpus: 2

setup: |
  conda create -n vllm python=3.10 -y
  conda activate vllm

  # Install Gradio for web UI.
  pip install gradio openai

run: |
  conda activate vllm
  export PATH=$PATH:/sbin

  echo 'Starting gradio server...'
  git clone https://github.com/vllm-project/vllm.git || true
  python vllm/examples/online_serving/gradio_openai_chatbot_webserver.py \
    -m $MODEL_NAME \
    --port 8811 \
    --model-url http://$ENDPOINT/v1 \
    --stop-token-ids 128009,128001 | tee ~/gradio.log

  1. 启动聊天 Web UI

    sky launch \
  -c gui ./gui.yaml \
  --env ENDPOINT=$(sky serve status --endpoint vllm)

  2. 然后，我们可以通过返回的 gradio 链接访问 GUI。

    | INFO | stdout | Running on public URL: https://6141e84201ce0bb4ed.gradio.live