'Attach the disk to the instance at mountpoint using info.'

def attach_volume(self, context, connection_info, instance, mountpoint, disk_bus=None, device_type=None, encryption=None):

    instance_name = instance.name
    if (instance_name not in self._mounts):
        self._mounts[instance_name] = {}
    self._mounts[instance_name][mountpoint] = connection_info
