add doc about serving option on dstack (#3074)

Co-authored-by: Roger Wang <ywang@roblox.com>

docs/source/serving/deploying_with_dstack.rst

@@ -0,0 +1,103 @@
+.. _deploying_with_dstack:
+
+Deploying with dstack
+============================
+
+.. raw:: html
+
+    <p align="center">
+        <img src="https://i.ibb.co/71kx6hW/vllm-dstack.png" alt="vLLM_plus_dstack"/>
+    </p>
+
+vLLM can be run on a cloud based GPU machine with `dstack <https://dstack.ai/>`__, an open-source framework for running LLMs on any cloud. This tutorial assumes that you have already configured credentials, gateway, and GPU quotas on your cloud environment.
+
+To install dstack client, run:
+
+.. code-block:: console
+
+    $ pip install "dstack[all]
+    $ dstack server
+
+Next, to configure your dstack project, run:
+    
+.. code-block:: console
+
+    $ mkdir -p vllm-dstack
+    $ cd vllm-dstack
+    $ dstack init
+
+Next, to provision a VM instance with LLM of your choice(`NousResearch/Llama-2-7b-chat-hf` for this example), create the following `serve.dstack.yml` file for the dstack `Service`:
+    
+.. code-block:: yaml
+
+    type: service
+    
+    python: "3.11"
+    env:
+        - MODEL=NousResearch/Llama-2-7b-chat-hf
+    port: 8000
+    resources:
+        gpu: 24GB
+    commands:
+        - pip install vllm
+        - python -m vllm.entrypoints.openai.api_server --model $MODEL --port 8000
+    model:
+        format: openai
+        type: chat
+        name: NousResearch/Llama-2-7b-chat-hf
+
+Then, run the following CLI for provisioning:
+
+.. code-block:: console
+
+    $ dstack run . -f serve.dstack.yml
+    
+    ⠸ Getting run plan...
+     Configuration  serve.dstack.yml             
+     Project        deep-diver-main              
+     User           deep-diver                   
+     Min resources  2..xCPU, 8GB.., 1xGPU (24GB) 
+     Max price      -                            
+     Max duration   -                            
+     Spot policy    auto                         
+     Retry policy   no                           
+    
+     #  BACKEND  REGION       INSTANCE       RESOURCES                               SPOT  PRICE       
+     1  gcp   us-central1  g2-standard-4  4xCPU, 16GB, 1xL4 (24GB), 100GB (disk)  yes   $0.223804   
+     2  gcp   us-east1     g2-standard-4  4xCPU, 16GB, 1xL4 (24GB), 100GB (disk)  yes   $0.223804   
+     3  gcp   us-west1     g2-standard-4  4xCPU, 16GB, 1xL4 (24GB), 100GB (disk)  yes   $0.223804   
+        ...                                                                                            
+     Shown 3 of 193 offers, $5.876 max
+    
+    Continue? [y/n]: y
+    ⠙ Submitting run...
+    ⠏ Launching spicy-treefrog-1 (pulling)
+    spicy-treefrog-1 provisioning completed (running)
+    Service is published at ...
+
+After the provisioning, you can interact with the model by using the OpenAI SDK:
+
+.. code-block:: python
+
+    from openai import OpenAI
+    
+    client = OpenAI(
+        base_url="https://gateway.<gateway domain>",
+        api_key="<YOUR-DSTACK-SERVER-ACCESS-TOKEN>"
+    )
+    
+    completion = client.chat.completions.create(
+        model="NousResearch/Llama-2-7b-chat-hf",
+        messages=[
+            {
+                "role": "user",
+                "content": "Compose a poem that explains the concept of recursion in programming.",
+            }
+        ]
+    )
+
+    print(completion.choices[0].message.content)
+
+.. note::
+
+    dstack automatically handles authentication on the gateway using dstack's tokens. Meanwhile, if you don't want to configure a gateway, you can provision dstack `Task` instead of `Service`. The `Task` is for development purpose only. If you want to know more about hands-on materials how to serve vLLM using dstack, check out `this repository <https://github.com/dstackai/dstack-examples/tree/main/deployment/vllm>`__

docs/source/serving/integrations.rst

@@ -9,4 +9,5 @@ Integrations
    deploying_with_triton
    deploying_with_bentoml
    deploying_with_lws
+   deploying_with_dstack
    serving_with_langchain