| 1 | # LiteLLM |
| 2 | |
| 3 | [LiteLLM](https://github.com/BerriAI/litellm) call all LLM APIs using the OpenAI format [Bedrock, Huggingface, VertexAI, TogetherAI, Azure, OpenAI, Groq etc.] |
| 4 | |
| 5 | LiteLLM manages: |
| 6 | |
| 7 | - Translate inputs to provider's `completion`, `embedding`, and `image_generation` endpoints |
| 8 | - [Consistent output](https://docs.litellm.ai/docs/completion/output), text responses will always be available at `['choices'][0]['message']['content']` |
| 9 | - Retry/fallback logic across multiple deployments (e.g. Azure/OpenAI) - [Router](https://docs.litellm.ai/docs/routing) |
| 10 | - Set Budgets & Rate limits per project, api key, model [LiteLLM Proxy Server (LLM Gateway)](https://docs.litellm.ai/docs/simple_proxy) |
| 11 | |
| 12 | And LiteLLM supports all models on VLLM. |
| 13 | |
| 14 | ## Prerequisites |
| 15 | |
| 16 | Set up the vLLM and litellm environment: |
| 17 | |
| 18 | ```bash |
| 19 | pip install vllm litellm |
| 20 | ``` |
| 21 | |
| 22 | ## Deploy |
| 23 | |
| 24 | ### Chat completion |
| 25 | |
| 26 | 1. Start the vLLM server with the supported chat completion model, e.g. |
| 27 | |
| 28 | ```bash |
| 29 | vllm serve qwen/Qwen1.5-0.5B-Chat |
| 30 | ``` |
| 31 | |
| 32 | 1. Call it with litellm: |
| 33 | |
| 34 | ??? code |
| 35 | |
| 36 | ```python |
| 37 | import litellm |
| 38 | |
| 39 | messages = [{"content": "Hello, how are you?", "role": "user"}] |
| 40 | |
| 41 | # hosted_vllm is prefix key word and necessary |
| 42 | response = litellm.completion( |
| 43 | model="hosted_vllm/qwen/Qwen1.5-0.5B-Chat", # pass the vllm model name |
| 44 | messages=messages, |
| 45 | api_base="http://{your-vllm-server-host}:{your-vllm-server-port}/v1", |
| 46 | temperature=0.2, |
| 47 | max_tokens=80, |
| 48 | ) |
| 49 | |
| 50 | print(response) |
| 51 | ``` |
| 52 | |
| 53 | ### Embeddings |
| 54 | |
| 55 | 1. Start the vLLM server with the supported embedding model, e.g. |
| 56 | |
| 57 | ```bash |
| 58 | vllm serve BAAI/bge-base-en-v1.5 |
| 59 | ``` |
| 60 | |
| 61 | 1. Call it with litellm: |
| 62 | |
| 63 | ```python |
| 64 | from litellm import embedding |
| 65 | import os |
| 66 | |
| 67 | os.environ["HOSTED_VLLM_API_BASE"] = "http://{your-vllm-server-host}:{your-vllm-server-port}/v1" |
| 68 | |
| 69 | # hosted_vllm is prefix key word and necessary |
| 70 | # pass the vllm model name |
| 71 | embedding = embedding(model="hosted_vllm/BAAI/bge-base-en-v1.5", input=["Hello world"]) |
| 72 | |
| 73 | print(embedding) |
| 74 | ``` |
| 75 | |
| 76 | For details, see the tutorial [Using vLLM in LiteLLM](https://docs.litellm.ai/docs/providers/vllm). |