Hi Mark When I use latest oslo, Oslo.config raises AttributeError instead of NoSuchOptError. (now devstack is using latest oslo, and this is also breaking neutron gating) Neutron agents handles NoSuchOptError, so this change brokes most of neutron agents. (see https://bugs.launchpad.net/oslo/+bug/1207541 ) I prefer NoSuchOptError than AtrtributeError, because NoSuchOptError has more info and it is subclass of AtrtributeError. At least, since this is API change, this change should be agreed on community. I would like to suggest to revert the change which makes this change. https://github.com/openstack/oslo.config/commit/305ecd817836a90a8f5e495cbf6a770dcea1f7e8 Best Nachi