Index: apache-libcloud-3.5.1/libcloud/compute/drivers/ec2.py
===================================================================
--- apache-libcloud-3.5.1.orig/libcloud/compute/drivers/ec2.py
+++ apache-libcloud-3.5.1/libcloud/compute/drivers/ec2.py
@@ -1622,12 +1622,18 @@ class BaseEC2NodeDriver(NodeDriver):
                                        on-demand price will be used.
         :type       ex_spot_max_price: ``float``
         """
+
+        try:
+            instance_type = size.id
+        except AttributeError:
+            instance_type = size
+
         params = {
             "Action": "RunInstances",
             "ImageId": image.id,
             "MinCount": str(ex_mincount),
             "MaxCount": str(ex_maxcount),
-            "InstanceType": size.id,
+            "InstanceType": instance_type,
         }
 
         if ex_terminate_on_shutdown: