I'm puzzled by nova instance rebuilds. When I run 'openstack server rebuild --image <whatever>' on a new test VM, it does what I expect: - throws away the old server image - boots up a brand new server using the requested image with the old user/vendor data - attaches new server to the old network port and cinder volumes. That's just what I want! Alas, when I try this with the actual old VMs in need of update, usually it does a totally different thing: - reboots the server - changes the nova db record to reflect the requested VM (so that the server /looks/ like it was rebuilt in 'openstack server show') - That's it! It absolutely does not rebuild the actual server disk image. So, for instance, any files that were present in '/' of the old server are still present post-rebuild. lsb_release still shows the OS of the original base image, disagreeing with the the OS version displayed by 'openstack server show'. I've been reading logfiles for days but I don't see nova ever complain (in either case) that it's doing something unexpected and in both cases the servers wind up in state 'Active'. Am I misunderstanding what this is supposed to do? If not, does anyone have thoughts about what might be going wrong? I assume nova is encountering a roadbump during the rebuild and doing a graceful revert, but if so it sure isn't telling me. Bobcat, kvm, VM images are hosted on ceph/rbd.