---
features:
  - It is possible to call attach and detach volume API operations for
    instances which are in shelved and shelved_offloaded state.
    For an instance in shelved_offloaded state Nova will set to None the value
    for the device_name field, the right value for that field will be set once
    the instance will be unshelved as it will be managed by a specific compute
    manager.
