[P/D] Add a shutdown method to the Connector API (#22699)

Signed-off-by: chaunceyjiang <chaunceyjiang@gmail.com>

vllm/distributed/kv_transfer/__init__.py

@@ -2,11 +2,12 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from vllm.distributed.kv_transfer.kv_transfer_state import (
-    KVConnectorBaseType, ensure_kv_transfer_initialized, get_kv_transfer_group,
-    has_kv_transfer_group, is_v1_kv_transfer_group)
+    KVConnectorBaseType, ensure_kv_transfer_initialized,
+    ensure_kv_transfer_shutdown, get_kv_transfer_group, has_kv_transfer_group,
+    is_v1_kv_transfer_group)
 
 __all__ = [
     "get_kv_transfer_group", "has_kv_transfer_group",
     "is_v1_kv_transfer_group", "ensure_kv_transfer_initialized",
-    "KVConnectorBaseType"
+    "ensure_kv_transfer_shutdown", "KVConnectorBaseType"
 ]

vllm/distributed/kv_transfer/kv_connector/v1/base.py

@@ -226,6 +226,14 @@ class KVConnectorBase_V1(ABC):
         """
         return None, None
 
+    def shutdown(self):
+        """
+        Shutdown the connector. This is called when the worker process
+        is shutting down to ensure that all the async operations are
+        completed and the connector is cleaned up properly.
+        """
+        return None
+
     # ==============================
     # Scheduler-side methods
     # ==============================

vllm/distributed/kv_transfer/kv_transfer_state.py

@@ -64,3 +64,10 @@ def ensure_kv_transfer_initialized(vllm_config: "VllmConfig") -> None:
                 config=vllm_config, role=KVConnectorRole.WORKER)
         else:
             raise ValueError("V0 is no longer supported")
+
+
+def ensure_kv_transfer_shutdown() -> None:
+    global _KV_CONNECTOR_AGENT
+    if _KV_CONNECTOR_AGENT is not None:
+        _KV_CONNECTOR_AGENT.shutdown()
+        _KV_CONNECTOR_AGENT = None

vllm/executor/executor_base.py

@@ -231,7 +231,7 @@ class ExecutorBase(ABC):
 
     def shutdown(self) -> None:
         """Shutdown the executor."""
-        return
+        self.collective_rpc("shutdown")
 
     def __del__(self):
         self.shutdown()

vllm/v1/core/sched/scheduler.py

@@ -1188,6 +1188,8 @@ class Scheduler(SchedulerInterface):
     def shutdown(self) -> None:
         if self.kv_event_publisher:
             self.kv_event_publisher.shutdown()
+        if self.connector is not None:
+            self.connector.shutdown()
 
     ########################################################################
     # KV Connector Related Methods

vllm/v1/executor/multiproc_executor.py

 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import multiprocessing
-import os
 import pickle
 import queue
 import signal
@@ -507,6 +506,7 @@ class WorkerProc:
         return cast(list[WorkerProcHandle], ready_proc_handles)
 
     def shutdown(self):
+        self.worker.shutdown()
         self.rpc_broadcast_mq = None
         self.worker_response_mq = None
         destroy_model_parallel()
@@ -536,7 +536,7 @@ class WorkerProc:
         # tuple[Connection, Connection]
         reader, ready_writer = kwargs.pop("ready_pipe")
         death_pipe = kwargs.pop("death_pipe", None)
-
+        shutdown_event = threading.Event()
         # Start death monitoring thread if death_pipe is provided
         if death_pipe is not None:
 
@@ -548,7 +548,7 @@ class WorkerProc:
                     # Parent process has exited, terminate this worker
                     logger.info("Parent process exited, terminating worker")
                     # Send signal to self to trigger clean shutdown
-                    os.kill(os.getpid(), signal.SIGTERM)
+                    shutdown_event.set()
                 except Exception as e:
                     logger.warning("Death monitoring error: %s", e)
 
@@ -576,7 +576,7 @@ class WorkerProc:
             ready_writer.close()
             ready_writer = None
 
-            worker.worker_busy_loop()
+            worker.worker_busy_loop(cancel=shutdown_event)
 
         except Exception:
             # NOTE: if an Exception arises in busy_loop, we send
@@ -586,6 +586,8 @@ class WorkerProc:
 
             if ready_writer is not None:
                 logger.exception("WorkerProc failed to start.")
+            elif shutdown_event.is_set():
+                logger.info("WorkerProc shutting down.")
             else:
                 logger.exception("WorkerProc failed.")
 
@@ -637,11 +639,11 @@ class WorkerProc:
             output = self.async_output_queue.get()
             self.enqueue_output(output)
 
-    def worker_busy_loop(self):
+    def worker_busy_loop(self, cancel: Optional[threading.Event] = None):
         """Main busy loop for Multiprocessing Workers"""
         while True:
-            method, args, kwargs, output_rank = self.rpc_broadcast_mq.dequeue()
-
+            method, args, kwargs, output_rank = self.rpc_broadcast_mq.dequeue(
+                cancel=cancel)
             try:
                 if isinstance(method, str):
                     func = getattr(self.worker, method)

vllm/v1/worker/gpu_worker.py

@@ -601,6 +601,9 @@ class Worker(WorkerBase):
         self.model_runner.save_tensorized_model(
             tensorizer_config=tensorizer_config, )
 
+    def shutdown(self) -> None:
+        self.model_runner.ensure_kv_transfer_shutdown()
+
 
 def init_worker_distributed_environment(
     vllm_config: VllmConfig,

vllm/v1/worker/kv_connector_model_runner_mixin.py

@@ -9,7 +9,8 @@ from typing import Generator  # noqa: UP035
 from typing import TYPE_CHECKING, Optional
 
 from vllm.config import VllmConfig
-from vllm.distributed.kv_transfer import (get_kv_transfer_group,
+from vllm.distributed.kv_transfer import (ensure_kv_transfer_shutdown,
+                                          get_kv_transfer_group,
                                           has_kv_transfer_group)
 from vllm.distributed.kv_transfer.kv_connector.base import KVConnectorBase
 from vllm.forward_context import get_forward_context, set_forward_context
@@ -42,6 +43,11 @@ class KVConnectorModelRunnerMixin:
             # Do this here to save a collective_rpc.
             kv_connector.start_load_kv(get_forward_context())
 
+    @staticmethod
+    def ensure_kv_transfer_shutdown() -> None:
+        if has_kv_transfer_group():
+            ensure_kv_transfer_shutdown()
+
     @staticmethod
     def maybe_wait_for_kv_save() -> None:
         if has_kv_transfer_group():

vllm/v1/worker/tpu_worker.py

@@ -330,6 +330,9 @@ class TPUWorker:
 
         ensure_kv_transfer_initialized(vllm_config)
 
+    def shutdown(self) -> None:
+        self.model_runner.ensure_kv_transfer_shutdown()
+
 
 if USE_TPU_COMMONS:
     from tpu_commons.worker import TPUWorker as TPUCommonsWorker

vllm/worker/worker_base.py

@@ -129,6 +129,10 @@ class WorkerBase:
         """Get vocabulary size from model configuration."""
         return self.model_config.get_vocab_size()
 
+    def shutdown(self) -> None:
+        """Clean up resources held by the worker."""
+        return
+
 
 class DelegateWorkerBase(WorkerBase):
     """
@@ -519,6 +523,10 @@ class WorkerWrapperBase:
                 from vllm.utils import init_cached_hf_modules
                 init_cached_hf_modules()
 
+    def shutdown(self) -> None:
+        if self.worker is not None:
+            self.worker.shutdown()
+
     def adjust_rank(self, rank_mapping: Dict[int, int]) -> None:
         """
         Adjust the rpc_rank based on the given mapping.