Support loading weights from remote instance (#8215)

Signed-off-by: Anqi Shen <amy.saq@antgroup.com>
Co-authored-by: Chayenne <74843776+zhaochenyang20@users.noreply.github.com>

python/sglang/srt/managers/scheduler.py

@@ -81,6 +81,8 @@ from sglang.srt.managers.io_struct import (
     GetInternalStateReqOutput,
     GetWeightsByNameReqInput,
     HealthCheckOutput,
+    InitWeightsSendGroupForRemoteInstanceReqInput,
+    InitWeightsSendGroupForRemoteInstanceReqOutput,
     InitWeightsUpdateGroupReqInput,
     LoadLoRAAdapterReqInput,
     LoadLoRAAdapterReqOutput,
@@ -93,6 +95,8 @@ from sglang.srt.managers.io_struct import (
     ResumeMemoryOccupationReqInput,
     RpcReqInput,
     RpcReqOutput,
+    SendWeightsToRemoteInstanceReqInput,
+    SendWeightsToRemoteInstanceReqOutput,
     SetInternalStateReq,
     SetInternalStateReqOutput,
     SlowDownReqInput,
@@ -538,6 +542,14 @@ class Scheduler(
                 (CloseSessionReqInput, self.close_session),
                 (UpdateWeightFromDiskReqInput, self.update_weights_from_disk),
                 (InitWeightsUpdateGroupReqInput, self.init_weights_update_group),
+                (
+                    InitWeightsSendGroupForRemoteInstanceReqInput,
+                    self.init_weights_send_group_for_remote_instance,
+                ),
+                (
+                    SendWeightsToRemoteInstanceReqInput,
+                    self.send_weights_to_remote_instance,
+                ),
                 (
                     UpdateWeightsFromDistributedReqInput,
                     self.update_weights_from_distributed,
@@ -2429,6 +2441,22 @@ class Scheduler(
         self.send_to_detokenizer.send_pyobj(recv_req)
         return recv_req
 
+    def init_weights_send_group_for_remote_instance(
+        self, recv_req: InitWeightsSendGroupForRemoteInstanceReqInput
+    ):
+        """Init the seed and client instance communication group."""
+        success, message = self.tp_worker.init_weights_send_group_for_remote_instance(
+            recv_req
+        )
+        return InitWeightsSendGroupForRemoteInstanceReqOutput(success, message)
+
+    def send_weights_to_remote_instance(
+        self, recv_req: SendWeightsToRemoteInstanceReqInput
+    ):
+        """Send the seed instance weights to the destination instance."""
+        success, message = self.tp_worker.send_weights_to_remote_instance(recv_req)
+        return SendWeightsToRemoteInstanceReqOutput(success, message)
+
     def slow_down(self, recv_req: SlowDownReqInput):
         t = recv_req.forward_sleep_time
         if t is not None and t <= 0: