[Frontend][Core] Re-add shutdown timeout - allowing in-flight requests to finish (#36666)

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Nick Hill <nickhill123@gmail.com>
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>
Co-authored-by: Nick Hill <nickhill123@gmail.com>

vllm/config/vllm.py

@@ -327,6 +327,12 @@ class VllmConfig:
     weight_transfer_config: WeightTransferConfig | None = None
     """The configurations for weight transfer during RL training."""
 
+    shutdown_timeout: int = Field(default=0, ge=0)
+    """Shutdown grace period for in-flight requests. Shutdown will be delayed for
+    up to this amount of time to allow already-running requests to complete. Any
+    remaining requests are aborted once the timeout is reached.
+    """
+
     def compute_hash(self) -> str:
         """
         WARNING: Whenever a new field is added to this config,