update docker compose structure with nvidia

Author: pranavvm26

src/sagemaker/local/image.py

@@ -340,7 +340,10 @@ def serve(self, model_dir, environment):
         self.container_root = self._create_tmp_folder()
         logger.info("creating hosting dir in %s", self.container_root)
 
-        volumes = self._prepare_serving_volumes(model_dir)
+        if model_dir is not None: 
+            volumes = self._prepare_serving_volumes(model_dir)
+        else:
+            volumes = None
 
         # If the user script was passed as a file:// mount it to the container.
         if sagemaker.estimator.DIR_PARAM_NAME.upper() in environment:
@@ -859,7 +862,7 @@ def _create_docker_host(
         if self.instance_type == "local_gpu":
             host_config["deploy"] = {
                 "resources": {
-                    "reservations": {"devices": [{"count": "all", "capabilities": ["gpu"]}]}
+                    "reservations": {"devices": [{"driver": "nvidia", "count": "all", "capabilities": ["gpu"]}]}
                 }
             }