'Instruct Cinder to manage a storage object.
Manages an existing backend storage object (e.g. a Linux logical
volume or a SAN disk) by creating the Cinder objects required to manage
it, and possibly renaming the backend storage object
(driver dependent)
From an API perspective, this operation behaves very much like a
volume creation operation, except that properties such as image,
snapshot and volume references don\'t make sense, because we are taking
an existing storage object into Cinder management.
Required HTTP Body:
.. code-block:: json
"volume": {
"host": "<Cinder host on which the existing storage resides>",
"cluster": "<Cinder cluster on which the storage resides>",
"ref": "<Driver-specific reference to existing storage object>"
See the appropriate Cinder drivers\' implementations of the
manage_volume method to find out the accepted format of \'ref\'.
This API call will return with an error if any of the above elements
are missing from the request, or if the \'host\' element refers to a
cinder host that is not registered.
The volume will later enter the error state if it is discovered that
\'ref\' is bad.
Optional elements to \'volume\' are::
name               A name for the new volume.
description        A description for the new volume.
volume_type        ID or name of a volume type to associate with
the new Cinder volume. Does not necessarily
guarantee that the managed volume will have the
properties described in the volume_type. The
driver may choose to fail if it identifies that
the specified volume_type is not compatible with
the backend storage object.
metadata           Key/value pairs to be associated with the new
volume.
availability_zone  The availability zone to associate with the new
volume.
bootable           If set to True, marks the volume as bootable.'

@wsgi.response(http_client.ACCEPTED)
def create(self, req, body):

    context = req.environ['cinder.context']
    authorize_manage(context)
    self.assert_valid_body(body, 'volume')
    volume = body['volume']
    self.validate_name_and_description(volume)
    if ('ref' not in volume):
        raise exception.MissingRequired(element='ref')
    (cluster_name, host) = common.get_cluster_host(req, volume, '3.16')
    LOG.debug('Manage    volume    request    body:    %s', body)
    kwargs = {}
    req_volume_type = volume.get('volume_type', None)
    if req_volume_type:
        try:
            kwargs['volume_type'] = volume_types.get_by_name_or_id(context, req_volume_type)
        except exception.VolumeTypeNotFound:
            msg = (_("Cannot    find    requested    '%s'    volume    type") % req_volume_type)
            raise exception.InvalidVolumeType(reason=msg)
    else:
        kwargs['volume_type'] = {}
    kwargs['name'] = volume.get('name', None)
    kwargs['description'] = volume.get('description', None)
    kwargs['metadata'] = volume.get('metadata', None)
    kwargs['availability_zone'] = volume.get('availability_zone', None)
    kwargs['bootable'] = utils.get_bool_param('bootable', volume)
    utils.check_metadata_properties(kwargs['metadata'])
    try:
        new_volume = self.volume_api.manage_existing(context, host, cluster_name, volume['ref'], **kwargs)
    except exception.ServiceNotFound:
        msg = (_("Host    '%s'    not    found") % volume['host'])
        raise exception.ServiceUnavailable(message=msg)
    utils.add_visible_admin_metadata(new_volume)
    return self._view_builder.detail(req, new_volume)
