The following _MAX_LEN constants are being removed from neutron/api/v2/attributes.py in [1]. The corresponding DB field size constants from neutron_lib.db.constants should be used instead. All subproject maintainers should update their code to use the the db *_FIELD_SIZE constants from neutron-lib. I have submitted patches [2] for most subprojects. NAME_MAX_LEN --> NAME_FIELD_SIZE TENANT_ID_MAX_LEN --> PROJECT_ID_FIELD_SIZE DESCRIPTION_MAX_LEN --> DESCRIPTION_FIELD_SIZE LONG_DESCRIPTION_MAX_LEN --> LONG_DESCRIPTION_FIELD_SIZE DEVICE_ID_MAX_LEN --> DEVICE_ID_FIELD_SIZE DEVICE_OWNER_MAX_LEN --> DEVICE_NAME_FIELD_SIZE In alembic migration scripts, the raw numerical value shall be used. For more information, see [3]. [1] https://review.openstack.org/399891 [2] https://review.openstack.org/#/q/status:open+topic:use-db-field-sizes [3] http://lists.openstack.org/pipermail/openstack-dev/2016-October/105789.html