Hi, All, In existing design, we need to reconfig nova.conf and restart nova service during post-upgrade cleanup As https://www.rdoproject.org/Upgrading_RDO_To_Icehouse: I propose to send RPC message to remove RPC API version pin. 1. Stop services (same with existing) 2. Upgrade packages (same with existing) 3. Upgrade DB schema (same with existint) 4. Start service with upgrade (add upgrade parameter so that nova will use old version of RPC API. We may add more parameter for other purpose including query upgrade progress) 5. Send RPC message to remove RPC API version pin. (we don't need to reconfig nova.conf and restart nova service) What do you think? Thanks, -Ruijing -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20150507/3cc3a6b8/attachment.html>