This is more of a sanity check than anything else: Does the RBDDriver in Diablo support live migration?
I was playing with this yesterday and couldn't get live migration to succeed. The errors I was getting seem to trace back to the fact that the RBDDriver doesn't override VolumeDriver's check_for_export call, which just defaults to "NotImplementedError". Looking at the latest Folsom code, there's still not a check_for_export call in the RBDDriver, which makes me think that the fact that in my PoC install (which I've switched between qcow2, iscsi and ceph repeatedly), I've somehow made something unhappy. 2012-07-24 13:44:29 TRACE nova.compute.manager [instance: 79c8c14f-43bf-4eaf-af94-bc578c82f921] [u'Traceback (most recent call last):\n', u' File "/usr/lib/python2.7/dist-packages/nova/rpc/amqp.py", line 253, in _process_data\n rval = node_func(context=ctxt, **node_args)\n', u' File "/usr/lib/python2.7/dist-packages/nova/volume/manager.py", line 294, in check_for_export\n self.driver.check_for_export(context, volume[\'id\'])\n', u' File "/usr/lib/python2.7/dist-packages/nova/volume/driver.py", line 459, in check_for_export\n tid = self.db.volume_get_iscsi_target_num(context, volume_id)\n', u' File "/usr/lib/python2.7/dist-packages/nova/db/api.py", line 983, in volume_get_iscsi_target_num\n return IMPL.volume_get_iscsi_target_num(context, volume_id)\n', u' File "/usr/lib/python2.7/dist-packages/nova/db/sqlalchemy/api.py", line 102, in wrapper\n return f(*args, **kwargs)\n', u' File "/usr/lib/python2.7/dist-packages/nova/db/sqlalchemy/api.py", line 2455, in volume_get_iscsi_target_num\n raise exception.ISCSITargetNotFoundForVolume(volume_id=volume_id)\n', u'ISCSITargetNotFoundForVolume: No target id found for volume 130.\n']. What's interesting here is that this KVM instance is only running RBD volumes, no iSCSI volumes in sight. Here's the drives as they're set up by openstack in the kvm command: -drive file=rbd:nova/volume-00000082:id=rbd:key=<...deleted my key...>==:auth_supported=cephx none,if=none,id=drive-virtio-disk0,format=raw,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive file=rbd:nova/volume-00000083:id=rbd:key=<...deleted my key...>==:auth_supported=cephx none,if=none,id=drive-virtio-disk1,format=raw,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virtio-disk1,id=virtio-disk1 But before banging my head against it more (and chastised after banging my head against the fiemap issue, which turned out to be an actual bug), I figured I'd see if it was even possible. In Sebastien Han's (completely fantastic) Ceph+Openstack article, it doesn't sound like he was able to get RBD-based migration working either. Again, I don't mind debugging further but wanted to make sure I wasn't debugging something that wasn't actually there. Incidentally, if I put something like this in /usr/lib/python2.7/dist-packages/nova/volume/manager.py in the for-loop if not volume[ "iscsi_target" ]: continue before the call to self.driver.check_for_export(), then live migration *seems* to work, but obviously I might be setting up some ugly corner case. If live migration isn't currently possible for RBD, anyone know if it's in a roadmap? _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : [email protected] Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
