[serve] Master actor fault tolerance (#8116)

python/ray/serve/backend_worker.py

@@ -23,24 +23,14 @@ def create_backend_worker(func_or_class):
         assert False, "func_or_class must be function or class."
 
     class RayServeWrappedWorker(object):
-        def __init__(self,
-                     backend_tag,
-                     replica_tag,
-                     init_args,
-                     router_handle=None):
+        def __init__(self, backend_tag, replica_tag, init_args):
             serve.init()
             if is_function:
                 _callable = func_or_class
             else:
                 _callable = func_or_class(*init_args)
 
-            if router_handle is None:
-                master_actor = serve.api._get_master_actor()
-                [router_handle] = ray.get(
-                    master_actor.get_backend_worker_config.remote())
-
-            self.backend = RayServeWorker(backend_tag, _callable,
-                                          router_handle, is_function)
+            self.backend = RayServeWorker(backend_tag, _callable, is_function)
 
         def get_metrics(self):
             return self.backend.get_metrics()
@@ -76,10 +66,9 @@ def ensure_async(func):
 class RayServeWorker:
     """Handles requests with the provided callable."""
 
-    def __init__(self, name, _callable, router_handle, is_function):
+    def __init__(self, name, _callable, is_function):
         self.name = name
         self.callable = _callable
-        self.router_handle = router_handle
         self.is_function = is_function
 
         self.error_counter = 0