run_on_sky.rst

.. _on_cloud:

Deploying and scaling up with SkyPilot
================================================

.. raw:: html

    <p align="center">
        <img src="https://imgur.com/yxtzPEu.png" alt="vLLM"/>
    </p>

vLLM can be **run and scaled to multiple service replicas on clouds and Kubernetes** with `SkyPilot <https://github.com/skypilot-org/skypilot>`__, an open-source framework for running LLMs on any cloud. More examples for various open models, such as Llama-3, Mixtral, etc, can be found in `SkyPilot AI gallery <https://skypilot.readthedocs.io/en/latest/gallery/index.html>`__.


Prerequisites
-------------

- Go to the `HuggingFace model page <https://huggingface.co/meta-llama/Meta-Llama-3-8B-Instruct>`__ and request access to the model :code:`meta-llama/Meta-Llama-3-8B-Instruct`.
- Check that you have installed SkyPilot (`docs <https://skypilot.readthedocs.io/en/latest/getting-started/installation.html>`__).
- Check that :code:`sky check` shows clouds or Kubernetes are enabled.

.. code-block:: console

    pip install skypilot-nightly
    sky check


Run on a single instance
------------------------

See the vLLM SkyPilot YAML for serving, `serving.yaml <https://github.com/skypilot-org/skypilot/blob/master/llm/vllm/serve.yaml>`__.

.. code-block:: 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/gradio_openai_chatbot_webserver.py \
            -m $MODEL_NAME \
            --port 8811 \
            --model-url http://localhost:8081/v1 \
            --stop-token-ids 128009,128001

Start the serving the Llama-3 8B model on any of the candidate GPUs listed (L4, A10g, ...): 

.. code-block:: console

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

Check the output of the command. There will be a shareable gradio link (like the last line of the following). Open it in your browser to use the LLaMA model to do the text completion.

.. code-block:: console

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

**Optional**: Serve the 70B model instead of the default 8B and use more GPU:

.. code-block:: console

    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


Scale up to multiple replicas
-----------------------------

SkyPilot can scale up the service to multiple service replicas with built-in autoscaling, load-balancing and fault-tolerance. You can do it by adding a services section to the YAML file.

.. code-block:: 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_tokens: 1
        
.. raw:: html

    <details>
    <summary>Click to see the full recipe YAML</summary>


.. code-block:: 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_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 &
        
        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/gradio_openai_chatbot_webserver.py \
            -m $MODEL_NAME \
            --port 8811 \
            --model-url http://localhost:8081/v1 \
            --stop-token-ids 128009,128001

.. raw:: html

    </details>

Start the serving the Llama-3 8B model on multiple replicas:

.. code-block:: console

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


Wait until the service is ready:

.. code-block:: console

    watch -n10 sky serve status vllm


.. raw:: html

    <details>
    <summary>Example outputs:</summary>

.. code-block:: console

    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({'L4': 1})  READY   us-east4
    vllm          2   1        xx.yy.zz.245  18 mins ago  1x GCP({'L4': 1})  READY   us-east4

.. raw:: html
    
    </details>

After the service is READY, you can find a single endpoint for the service and access the service with the endpoint:

.. code-block:: console

    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]
        }'

To enable autoscaling, you could specify additional configs in `services`:

.. code-block:: yaml

    services:
        replica_policy:
            min_replicas: 0
            max_replicas: 3
        target_qps_per_replica: 2

This will scale the service up to when the QPS exceeds 2 for each replica.


**Optional**: Connect a GUI to the endpoint
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


It is also possible to access the Llama-3 service with a separate GUI frontend, so the user requests send to the GUI will be load-balanced across replicas.

.. raw:: html

    <details>
    <summary>Click to see the full GUI YAML</summary>

.. code-block:: yaml

    envs:
        MODEL_NAME: meta-llama/Meta-Llama-3-70B-Instruct
        ENDPOINT: x.x.x.x:3031 # Address of the API server running vllm. 

    resources:
        cpus: 2

    setup: |
        conda activate vllm
        if [ $? -ne 0 ]; then
            conda create -n vllm python=3.10 -y
            conda activate vllm
        fi

        # Install Gradio for web UI.
        pip install gradio openai

    run: |
        conda activate vllm
        export PATH=$PATH:/sbin
        WORKER_IP=$(hostname -I | cut -d' ' -f1)
        CONTROLLER_PORT=21001
        WORKER_PORT=21002

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

.. raw:: html
    
    </details>

1. Start the chat web UI:

.. code-block:: console

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


2. Then, we can access the GUI at the returned gradio link:

.. code-block:: console

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