I reproduced this bug, when I did rebuild it is actually showing the new image in 'nova show' but it is actually booting from volume not the new image and the volume is not detached and is still associated to the vm. So vm remains same.
I reproduced this bug, when I did rebuild it is actually showing the new image in 'nova show' but it is actually booting from volume not the new image and the volume is not detached and is still associated to the vm. So vm remains same.