fix get_ip error in pure ipv6 environment (#2931)

Author: Jingru

vllm/utils.py

@@ -162,19 +162,33 @@ def _async_wrapper(*args, **kwargs) -> asyncio.Future:
 
 
 def get_ip() -> str:
+    # try ipv4
     s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-    s.connect(("8.8.8.8", 80))  # Doesn't need to be reachable
-    return s.getsockname()[0]
+    try:
+        s.connect(("dns.google", 80))  # Doesn't need to be reachable
+        return s.getsockname()[0]
+    except OSError:
+        # try ipv6
+        s = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
+        s.connect(("dns.google", 80))
+        return s.getsockname()[0]
 
 
 def get_distributed_init_method(ip: str, port: int) -> str:
     return f"tcp://{ip}:{port}"
 
 
 def get_open_port() -> int:
-    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
-        s.bind(("", 0))
-        return s.getsockname()[1]
+    # try ipv4
+    try:
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+            s.bind(("", 0))
+            return s.getsockname()[1]
+    except OSError:
+        # try ipv6
+        with socket.socket(socket.AF_INET6, socket.SOCK_STREAM) as s:
+            s.bind(("", 0))
+            return s.getsockname()[1]
 
 
 def set_cuda_visible_devices(device_ids: List[int]) -> None: