'Context manager to handle the pre and post instance boot,
LXC specific disk operations.
An image or a volume path will be prepared and setup to be
used by the container, prior to starting it.
The disk will be disconnected and unmounted if a container has
failed to start.'

@contextlib.contextmanager
def _lxc_disk_handler(self, instance, image_meta, block_device_info):

    if (CONF.libvirt.virt_type != 'lxc'):
        (yield)
        return
    self._create_domain_setup_lxc(instance, image_meta, block_device_info)
    try:
        (yield)
    finally:
        self._create_domain_cleanup_lxc(instance)
