[PD] Remove the requirement of config file for mooncake backend (#5460)

python/sglang/srt/server_args.py

@@ -196,6 +196,7 @@ class ServerArgs:
     disaggregation_mode: str = "null"
     disaggregation_bootstrap_port: int = 8998
     disaggregation_transfer_backend: str = "mooncake"
+    disaggregation_ib_device: Optional[str] = None
 
     def __post_init__(self):
         # Expert parallelism
@@ -1193,6 +1194,12 @@ class ServerArgs:
             default=ServerArgs.disaggregation_transfer_backend,
             help="The backend for disaggregation transfer. Default is mooncake.",
         )
+        parser.add_argument(
+            "--disaggregation-ib-device",
+            type=str,
+            default=ServerArgs.disaggregation_ib_device,
+            help="The ib device for disaggregation transfer. Default is None, it will be detected automatically if using the mooncake backend.",
+        )
 
     @classmethod
     def from_cli_args(cls, args: argparse.Namespace):