[Bugfix][DP] DP distribution does not require ray[default] (#23822)

Signed-off-by: Kebe <mail@kebe7jun.com>

Author: kebe7jun

vllm/v1/engine/utils.py

@@ -315,7 +315,6 @@ def create_dp_placement_groups(
 
         import ray
         from ray._private.state import available_resources_per_node
-        from ray.util.state import list_nodes
 
         logger.info("Creating placement groups for data parallel")
         dp_master_ip = \
@@ -324,31 +323,28 @@ def create_dp_placement_groups(
         local_engine_count = \
             vllm_config.parallel_config.data_parallel_size_local
 
-        nodes = sorted(list_nodes(filters=[("state", "=", "ALIVE")]),
-                       key=lambda node: node.node_ip != dp_master_ip)
-        assert nodes[0].node_ip == dp_master_ip, (
-            "The head node is missing or dead")
-        assert len(nodes) == 1 or nodes[1].node_ip != dp_master_ip, (
-            "There can only be one head node")
-
         available_resources = available_resources_per_node()
         world_size = vllm_config.parallel_config.world_size
         placement_groups: list[PlacementGroup] = []
         local_dp_ranks: list[int] = []
-
-        for node in nodes:
-            node_ip = node.node_ip
-            node_resources = available_resources[node.node_id]
+        dp_master_ip_key = f'node:{dp_master_ip}'
+        nodes = sorted(available_resources.values(),
+                       key=lambda x: dp_master_ip_key not in x)
+        assert len(nodes) > 0, (
+            "No nodes with resources found in Ray cluster.")
+        assert dp_master_ip_key in nodes[0], (
+            "The DP master node (ip: %s) is missing or dead", dp_master_ip)
+        for node_resources in nodes:
             if "GPU" not in node_resources:
                 continue
             # For now, each DP rank can only be assigned to one node
             # TODO(rui): support allocating a single DP rank
             # to multiple nodes
             available_engine_count = int(node_resources["GPU"]) // world_size
-            if node_ip == dp_master_ip:
+            if dp_master_ip_key in node_resources:
                 assert available_engine_count >= local_engine_count, (
                     "Not enough resources to allocate DP ranks "
-                    f"on DP master node {node_ip}")
+                    f"on DP master node {dp_master_ip}")
                 for i in range(local_engine_count):
                     bundles = [{
                         "GPU": 1.0,