Rename custom disk for simulated ssd backed instances

ec2stack/configure.py

diff --git a/ec2stack/configure.py b/ec2stack/configure.py
index a80b70d..5c4ffee 100644
--- a/ec2stack/configure.py
+++ b/ec2stack/configure.py
@@ -169,13 +169,13 @@
     @return: configparser configuration.
     """
 
-    configure_instance_type_mapings = raw_input(
-        'Do you wish to input a local custom storage disk for instances? (Yes/No): '
+    configure_instance_disk = raw_input(
+        'Do you wish to input a second custom storage disk for instances? (Yes/No): '
     )
 
-    if configure_instance_type_mapings.lower() in ['yes', 'y']:
+    if configure_instance_disk.lower() in ['yes', 'y']:
         config = _set_attribute_of_profile(
-            config, profile, 'cloudstack_local_custom_disk_offering', 'Cloudstack custom local disk offering name', 'CustomLocal'
+            config, profile, 'cloudstack_instance_custom_disk_offering', 'Cloudstack custom instance disk offering name', 'CustomInstance'
         )
 
     configure_instance_type_mapings = raw_input(

ec2stack/providers/cloudstack/instances.py

diff --git a/ec2stack/providers/cloudstack/instances.py b/ec2stack/providers/cloudstack/instances.py
index 84aa429..3e8115b 100644
--- a/ec2stack/providers/cloudstack/instances.py
+++ b/ec2stack/providers/cloudstack/instances.py
@@ -9,7 +9,7 @@
 
 from ec2stack.providers import cloudstack
 from ec2stack.providers.cloudstack import requester, service_offerings, zones, \
-    disk_offerings, volumes
+    disk_offerings
 from ec2stack import helpers, errors
 
 
@@ -178,9 +178,15 @@
     if helpers.get('BlockDeviceMapping.1.Ebs.VolumeType') is not None:
         disk_type = helpers.get('BlockDeviceMapping.1.Ebs.VolumeType')
         if disk_type == 'gp2':
-            args['diskofferingid'] = disk_offerings.get_disk_offering(
-                current_app.config['CLOUDSTACK_LOCAL_CUSTOM_DISK_OFFERING']
-            )['id']
+             if 'CLOUDSTACK_INSTANCE_CUSTOM_DISK_OFFERING' in current_app.config:
+                args['diskofferingid'] = disk_offerings.get_disk_offering(
+                    current_app.config['CLOUDSTACK_INSTANCE_CUSTOM_DISK_OFFERING']
+                )['id']
+             else:
+                errors.invalid_request(
+                    "Unable to configure secondary disk, please run ec2stack-configure and choose to "
+                    "configure an instance disk")
+
         if helpers.get('BlockDeviceMapping.1.Ebs.VolumeSize') is None:
             errors.invalid_request("VolumeSize not found in BlockDeviceMapping")
         else: