This seems like something that would have to be expressed from the cinder side based on the volume type.
Currently the libvirt driver gets the os-brick volume connector and passes that use_multipath value in here: https://github.com/openstack/nova/blob/14.0.1/nova/virt/libvirt/driver.py#L1033 That's the connector that nova passes to os-initialize_connection in cinder which gives back the connection_info used when connecting the volume to the host. So nova would need to know if it should use multipath or not before that, which we could maybe get from the volume/volume_type if cinder provided that information. Otherwise this is just how it's always worked. If cinder started providing that info, it would have to probably be in a microversion in the cinder v3 API. ** Changed in: nova Importance: Undecided => Wishlist ** Changed in: nova Status: New => Opinion ** Summary changed: - Use of iscsi_multipath should not be mandatory + Use of CONF.libvirt.volume_use_multipath should not be mandatory -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1639350 Title: Use of CONF.libvirt.volume_use_multipath should not be mandatory Status in OpenStack Compute (nova): Opinion Status in os-brick: New Bug description: Currently if iscsi_multipath is set in nova.conf we require ALL attachments to use multipath. The problem with this is that it's not uncommon to have a mix of Cinder backends; one that supports multipath and one that doesn't. The result with how we do this now is that you can have only one or the other but not both. We should be able to revert to single-path when multipath doesn't work for the volume; also might be worth considering if the multipath support should just be embedded as part of the volume object and skip the need to configure it in Nova at all. To reproduce, set up a default devstack with LIO and LVM; set nova.conf iscsi_multipath=True, restart nova. Create a volume, create an instance, try and attach the volume to the instance. Example stack trace here: http://paste.openstack.org/show/587939/ To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1639350/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : [email protected] Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
