Use custom address for listening socket (#15988)

Signed-off-by: Jens Glaser <glaserj@ornl.gov>

vllm/distributed/utils.py

@@ -7,6 +7,7 @@
 import dataclasses
 import datetime
 import pickle
+import socket
 import time
 from collections import deque
 from typing import Any, Deque, Dict, Optional, Sequence, Tuple
@@ -123,6 +124,10 @@ class StatelessProcessGroup:
     rank: int
     world_size: int
     store: torch._C._distributed_c10d.Store
+
+    # stores a reference to the socket so that the file descriptor stays alive
+    socket: Optional[socket.socket]
+
     data_expiration_seconds: int = 3600  # 1 hour
 
     # dst rank -> counter
@@ -234,18 +239,33 @@ class StatelessProcessGroup:
         can call `StatelessProcessGroup.create` to form a group, and then process A, B,
         C, and D can call `StatelessProcessGroup.create` to form another group.
         """ # noqa
+        launch_server = rank == 0
+        if launch_server:
+            # listen on the specified interface (instead of 0.0.0.0)
+            listen_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            listen_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+            listen_socket.bind((host, port))
+            listen_socket.listen()
+            listen_fd = listen_socket.fileno()
+        else:
+            listen_socket = None
+            listen_fd = None
+
         store = TCPStore(
             host_name=host,
             port=port,
             world_size=world_size,
-            is_master=(rank == 0),
+            is_master=launch_server,
             timeout=datetime.timedelta(seconds=store_timeout),
+            use_libuv=False,  # for now: github.com/pytorch/pytorch/pull/150215
+            master_listen_fd=listen_fd,
         )
 
         return StatelessProcessGroup(
             rank=rank,
             world_size=world_size,
             store=store,
+            socket=listen_socket,
             data_expiration_seconds=data_expiration_seconds)