retype does go through scheduler (https://github.com/openstack/cinder/blob/master/cinder/volume/api.py#L1417) and scheduler does verifies the input (extra specs for the new type) against all possible candidates (https://github.com/openstack/cinder/blob/master/cinder/scheduler/manager.py#L222, https://github.com/openstack/cinder/blob/master/cinder/scheduler/filter_scheduler.py#L124).
retype does go through scheduler (https:/ /github. com/openstack/ cinder/ blob/master/ cinder/ volume/ api.py# L1417) and scheduler does verifies the input (extra specs for the new type) against all possible candidates (https:/ /github. com/openstack/ cinder/ blob/master/ cinder/ scheduler/ manager. py#L222, https:/ /github. com/openstack/ cinder/ blob/master/ cinder/ scheduler/ filter_ scheduler. py#L124).