diff --git a/api-ref/source/v3/attachments.inc b/api-ref/source/v3/attachments.inc
index 4ea253951d1..87b57d6092c 100644
--- a/api-ref/source/v3/attachments.inc
+++ b/api-ref/source/v3/attachments.inc
@@ -253,7 +253,7 @@ Request
 
    - project_id: project_id_path
    - attachment: attachment
-   - instance_uuid: instance_uuid_req
+   - instance_uuid: instance_uuid
    - connector: connector
    - volume_uuid: volume_id_attachment
    - mode: attach_mode
diff --git a/cinder/api/schemas/attachments.py b/cinder/api/schemas/attachments.py
index cc03461c4d5..bd434954821 100644
--- a/cinder/api/schemas/attachments.py
+++ b/cinder/api/schemas/attachments.py
@@ -17,6 +17,7 @@
 Schema for V3 Attachments API.
 
 """
+import copy
 
 from cinder.api.validation import parameter_types
 
@@ -32,7 +33,7 @@
                 'connector': {'type': ['object', 'null']},
                 'volume_uuid': parameter_types.uuid,
             },
-            'required': ['instance_uuid', 'volume_uuid'],
+            'required': ['volume_uuid'],
             'additionalProperties': False,
         },
     },
@@ -56,3 +57,7 @@
     'required': ['attachment'],
     'additionalProperties': False,
 }
+
+create_v354 = copy.deepcopy(create)
+create_v354['properties']['attachment']['properties']['mode'] = (
+    {'type': 'string', 'enum': ['rw', 'ro']})
diff --git a/cinder/api/v3/attachments.py b/cinder/api/v3/attachments.py
index fa01cb5467f..f0c4110ccb5 100644
--- a/cinder/api/v3/attachments.py
+++ b/cinder/api/v3/attachments.py
@@ -107,7 +107,9 @@ def _items(self, req):
 
     @wsgi.Controller.api_version(mv.NEW_ATTACH)
     @wsgi.response(HTTPStatus.OK)
-    @validation.schema(attachment.create)
+    @validation.schema(attachment.create, mv.NEW_ATTACH,
+                       mv.get_prior_version(mv.ATTACHMENT_CREATE_MODE_ARG))
+    @validation.schema(attachment.create_v354, mv.ATTACHMENT_CREATE_MODE_ARG)
     def create(self, req, body):
         """Create an attachment.
 
@@ -130,6 +132,9 @@ def create(self, req, body):
         referenced below is the UUID of the Instance, for non-nova consumers
         this can be a server UUID or some other arbitrary unique identifier.
 
+        Starting from microversion 3.54, we can pass the attach mode as
+        argument in the request body.
+
         Expected format of the input parameter 'body':
 
         .. code-block:: json
@@ -138,8 +143,9 @@ def create(self, req, body):
                 "attachment":
                 {
                     "volume_uuid": "volume-uuid",
-                    "instance_uuid": "nova-server-uuid",
-                    "connector": "null|<connector-object>"
+                    "instance_uuid": "null|nova-server-uuid",
+                    "connector": "null|<connector-object>",
+                    "mode": "null|rw|ro"
                 }
             }
 
@@ -167,7 +173,7 @@ def create(self, req, body):
         returns: A summary view of the attachment object
         """
         context = req.environ['cinder.context']
-        instance_uuid = body['attachment']['instance_uuid']
+        instance_uuid = body['attachment'].get('instance_uuid')
         volume_uuid = body['attachment']['volume_uuid']
         volume_ref = objects.Volume.get_by_id(
             context,