[V0] Support multiple kv connectors

[maobaolong]

Motivation

Inspired by #17564 which make v1 support multiple connectors co-exist.

This PR aimed to implement MultiConnectorV0 for v0.

How to test

Start a 1P 1D cluster, and use lmcacheConnector as an offload purpose connector in the P instance, use FSConnector in the both P and D instance as a PD transfer connector.(Will submit another PR for introduce FSConnector, but you can use any other connector instead as P/D transfer connector)

• run an vllm instance for prefill role

CUDA_VISIBLE_DEVICES=0 \
VLLM_LOGGING_LEVEL=DEBUG \
LMCACHE_USE_EXPERIMENTAL=True LMCACHE_TRACK_USAGE=false LMCACHE_LOG_LEVEL=DEBUG \
LMCACHE_CONFIG_FILE=/disc/data1/baoloongmao/cpu/lmcache-cpu.yaml \
VLLM_MLA_DISABLE=1 VLLM_USE_V1=0 \
vllm serve /disc/data1/deepseek/DeepSeek-V2-Lite-Chat/ \
           --trust-remote-code \
           --served-model-name vllm_cpu_offload \
           --max-model-len 32768 \
           --max-seq-len-to-capture 10000 \
           --max-num-seqs 64 \
           --gpu-memory-utilization 0.9 \
           --host 0.0.0.0 \
           -tp 1 \
           --no-enable-prefix-caching \
           --max-num-batched-tokens 64000 \
           --kv-transfer-config '{"kv_connector":"MultiConnectorV0","kv_role":"kv_both","kv_connector_extra_config":{"connectors":[{"kv_connector":"FSConnector","kv_role":"kv_producer","kv_connector_extra_config":{"fs_storage_path":"fs_local_storage","transfer":true}},{"kv_connector":"LMCacheConnector","kv_role":"kv_both"}]}}'

• run an vllm instance for decode role

CUDA_VISIBLE_DEVICES=1 \
VLLM_LOGGING_LEVEL=DEBUG \
LMCACHE_USE_EXPERIMENTAL=True LMCACHE_TRACK_USAGE=false LMCACHE_LOG_LEVEL=DEBUG \
LMCACHE_CONFIG_FILE=/disc/data1/baoloongmao/cpu/lmcache-cpu.yaml \
VLLM_MLA_DISABLE=1 VLLM_USE_V1=0 \
vllm serve /disc/data1/deepseek/DeepSeek-V2-Lite-Chat/ \
           --trust-remote-code \
           --served-model-name vllm_cpu_offload \
           --max-model-len 32768 \
           --max-seq-len-to-capture 10000 \
           --max-num-seqs 64 \
           --gpu-memory-utilization 0.9 \
           --host 0.0.0.0 \
           -tp 1 \
           --no-enable-prefix-caching \
           --max-num-batched-tokens 64000 \
           --kv-transfer-config '{"kv_connector":"FSConnector","kv_role":"kv_consumer","kv_connector_extra_config":{"fs_storage_path":"fs_local_storage"}}' \
           --port 8001

• Send request by curl and check the output log and file in the fs_local_storage folder

curl http://localhost:8000/v1/chat/completions     -H "Content-Type: application/json"     -d '{
    "model": "vllm_cpu_offload",
    "messages": [{"role": "user", "content": "Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?"}],
    "max_tokens": 1,
    "temperature": 0,
    "top_p": 0.95
    }'
{"id":"chatcmpl-94b0c6c0941343af9499f895789febe1","object":"chat.completion","created":1747727609,"model":"vllm_cpu_offload","choices":[{"index":0,"message":{"role":"assistant","reasoning_content":null,"content":" Hello","tool_calls":[]},"logprobs":null,"finish_reason":"length","stop_reason":null}],"usage":{"prompt_tokens":409,"total_tokens":410,"completion_tokens":1,"prompt_tokens_details":null},"prompt_logprobs":null,"kv_transfer_params":null}

curl http://localhost:8001/v1/chat/completions     -H "Content-Type: application/json"     -d '{
    "model": "vllm_cpu_offload",
    "messages": [{"role": "user", "content": "Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?"}],
    "max_tokens": 10,
    "temperature": 0,
    "top_p": 0.95
    }'

• log in P

INFO 05-20 00:52:26 [logger.py:39] Received request chatcmpl-4c385ad864cb426dab9c3e31c82d073c: prompt: '<｜begin▁of▁sentence｜>User: Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?\n\nAssistant:', params: SamplingParams(n=1, presence_penalty=0.0, frequency_penalty=0.0, repetition_penalty=1.0, temperature=0.0, top_p=1.0, top_k=0, min_p=0.0, seed=None, stop=[], stop_token_ids=[], bad_words=[], include_stop_str_in_output=False, ignore_eos=False, max_tokens=1, min_tokens=0, logprobs=None, prompt_logprobs=None, skip_special_tokens=True, spaces_between_special_tokens=True, truncate_prompt_tokens=None, guided_decoding=None, extra_args=None), prompt_token_ids: None, lora_request: None, prompt_adapter_request: None.
INFO 05-20 00:52:26 [engine.py:313] Added request chatcmpl-4c385ad864cb426dab9c3e31c82d073c.
[2025-05-20 00:52:26,864] LMCache DEBUG: Retrieved 0 out of 409 out of total 409 tokens (cache_engine.py:330:lmcache.experimental.cache_engine)
[2025-05-20 00:52:26,864] LMCache DEBUG: Injected token number: 0 (vllm_adapter.py:747:lmcache.integration.vllm.vllm_adapter)
[2025-05-20 00:52:26,864] LMCache DEBUG: Returning the original input! (vllm_adapter.py:789:lmcache.integration.vllm.vllm_adapter)
DEBUG 05-20 00:52:27 [fs_connector.py:94] [rank0]: KV send DONE.
INFO 05-20 00:52:27 [multi_connector.py:67] sent to connector FSConnector
[2025-05-20 00:52:27,062] LMCache DEBUG: Stored 409 out of total 409 tokens (cache_engine.py:257:lmcache.experimental.cache_engine)
[2025-05-20 00:52:27,062] LMCache DEBUG: Store skips 0 tokens and then stores 409 tokens (vllm_adapter.py:561:lmcache.integration.vllm.vllm_adapter)
INFO 05-20 00:52:27 [multi_connector.py:67] sent to connector LMCacheConnector

INFO 05-20 00:52:57 [logger.py:39] Received request chatcmpl-ae3020fdc9974caaaea4167112dcba5b: prompt: '<｜begin▁of▁sentence｜>User: Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?\n\nAssistant:', params: SamplingParams(n=1, presence_penalty=0.0, frequency_penalty=0.0, repetition_penalty=1.0, temperature=0.0, top_p=1.0, top_k=0, min_p=0.0, seed=None, stop=[], stop_token_ids=[], bad_words=[], include_stop_str_in_output=False, ignore_eos=False, max_tokens=1, min_tokens=0, logprobs=None, prompt_logprobs=None, skip_special_tokens=True, spaces_between_special_tokens=True, truncate_prompt_tokens=None, guided_decoding=None, extra_args=None), prompt_token_ids: None, lora_request: None, prompt_adapter_request: None.
INFO 05-20 00:52:57 [engine.py:313] Added request chatcmpl-ae3020fdc9974caaaea4167112dcba5b.
[2025-05-20 00:52:57,507] LMCache DEBUG: Retrieved 409 out of 409 out of total 409 tokens (cache_engine.py:330:lmcache.experimental.cache_engine)
[2025-05-20 00:52:57,507] LMCache DEBUG: Injected token number: 408 (vllm_adapter.py:747:lmcache.integration.vllm.vllm_adapter)
[2025-05-20 00:52:57,517] LMCache DEBUG: Rebuilt the input! (vllm_adapter.py:786:lmcache.integration.vllm.vllm_adapter)
DEBUG 05-20 00:52:57 [fs_connector.py:94] [rank0]: KV send DONE.
INFO 05-20 00:52:57 [multi_connector.py:67] sent to connector FSConnector
[2025-05-20 00:52:57,558] LMCache DEBUG: Store skips 409 tokens and then stores 0 tokens (vllm_adapter.py:561:lmcache.integration.vllm.vllm_adapter)
INFO 05-20 00:52:57 [multi_connector.py:67] sent to connector LMCacheConnector

INFO 05-20 00:53:29 [logger.py:39] Received request chatcmpl-94b0c6c0941343af9499f895789febe1: prompt: '<｜begin▁of▁sentence｜>User: Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?\n\nAssistant:', params: SamplingParams(n=1, presence_penalty=0.0, frequency_penalty=0.0, repetition_penalty=1.0, temperature=0.0, top_p=1.0, top_k=0, min_p=0.0, seed=None, stop=[], stop_token_ids=[], bad_words=[], include_stop_str_in_output=False, ignore_eos=False, max_tokens=1, min_tokens=0, logprobs=None, prompt_logprobs=None, skip_special_tokens=True, spaces_between_special_tokens=True, truncate_prompt_tokens=None, guided_decoding=None, extra_args=None), prompt_token_ids: None, lora_request: None, prompt_adapter_request: None.
INFO 05-20 00:53:29 [engine.py:313] Added request chatcmpl-94b0c6c0941343af9499f895789febe1.
[2025-05-20 00:53:29,635] LMCache DEBUG: Retrieved 409 out of 409 out of total 409 tokens (cache_engine.py:330:lmcache.experimental.cache_engine)
[2025-05-20 00:53:29,635] LMCache DEBUG: Injected token number: 408 (vllm_adapter.py:747:lmcache.integration.vllm.vllm_adapter)
[2025-05-20 00:53:29,638] LMCache DEBUG: Rebuilt the input! (vllm_adapter.py:786:lmcache.integration.vllm.vllm_adapter)
DEBUG 05-20 00:53:29 [fs_connector.py:94] [rank0]: KV send DONE.
INFO 05-20 00:53:29 [multi_connector.py:67] sent to connector FSConnector
[2025-05-20 00:53:29,671] LMCache DEBUG: Store skips 409 tokens and then stores 0 tokens (vllm_adapter.py:561:lmcache.integration.vllm.vllm_adapter)
INFO 05-20 00:53:29 [multi_connector.py:67] sent to connector LMCacheConnector

• log in D

INFO 05-20 00:52:46 [logger.py:39] Received request chatcmpl-471ab3691c8741768686f04e4a3123f1: prompt: '<｜begin▁of▁sentence｜>User: Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?\n\nAssistant:', params: SamplingParams(n=1, presence_penalty=0.0, frequency_penalty=0.0, repetition_penalty=1.0, temperature=0.0, top_p=1.0, top_k=0, min_p=0.0, seed=None, stop=[], stop_token_ids=[], bad_words=[], include_stop_str_in_output=False, ignore_eos=False, max_tokens=10, min_tokens=0, logprobs=None, prompt_logprobs=None, skip_special_tokens=True, spaces_between_special_tokens=True, truncate_prompt_tokens=None, guided_decoding=None, extra_args=None), prompt_token_ids: None, lora_request: None, prompt_adapter_request: None.
INFO 05-20 00:52:46 [engine.py:313] Added request chatcmpl-471ab3691c8741768686f04e4a3123f1.
DEBUG 05-20 00:52:46 [fs_connector.py:170] [rank0]: Successfully received all KVs and hidden states, skip model forwarding.

INFO 05-20 00:53:09 [logger.py:39] Received request chatcmpl-d0deb766738a425aa0129134ef52955e: prompt: '<｜begin▁of▁sentence｜>User: Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?Hello, how are you?\n\nAssistant:', params: SamplingParams(n=1, presence_penalty=0.0, frequency_penalty=0.0, repetition_penalty=1.0, temperature=0.0, top_p=1.0, top_k=0, min_p=0.0, seed=None, stop=[], stop_token_ids=[], bad_words=[], include_stop_str_in_output=False, ignore_eos=False, max_tokens=10, min_tokens=0, logprobs=None, prompt_logprobs=None, skip_special_tokens=True, spaces_between_special_tokens=True, truncate_prompt_tokens=None, guided_decoding=None, extra_args=None), prompt_token_ids: None, lora_request: None, prompt_adapter_request: None.
INFO 05-20 00:53:09 [engine.py:313] Added request chatcmpl-d0deb766738a425aa0129134ef52955e.
DEBUG 05-20 00:53:09 [fs_connector.py:170] [rank0]: Successfully received all KVs and hidden states, skip model forwarding.

[github-actions]

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🚀

[maobaolong]

@mgoin @njhill Would you like to take a look at this PR? Thanks!

[maobaolong]

Would be great if you could review this PR! @mgoin @njhill