'Quiesce the specified instance to prepare for snapshots.
If the specified instance doesn\'t support quiescing,
InstanceQuiesceNotSupported is raised. When it fails to quiesce by
other errors (e.g. agent timeout), NovaException is raised.
:param context:  request context
:param instance: nova.objects.instance.Instance to be quiesced
:param nova.objects.ImageMeta image_meta:
The metadata of the image of the instance.'

def quiesce(self, context, instance, image_meta):

    raise NotImplementedError()
