Description of problem: After configuring multipath as per doc for iscsi unity cinder driver , nova is not able to find mpath device for the volume . The instance ends up getting single path device. Version-Release number of selected component (if applicable): python-os-brick-1.11.0-1.el7ost.noarch RHOS11 How reproducible: Always in customer environment Steps to Reproduce: 1. 2. 3. Actual results: nova-compute logs that mpath device is not visible although the device is visible in multipath -ll . Expected results: nova-compute uses the mpath device for the corresponding volume. Additional info: nova-compute.log 2017-08-06 22:38:26.394 256626 WARNING os_brick.initiator.linuxscsi [req-29b5393b-cbec-468d-ac81-7f7fe666ead4 57ebc072672d48eca08779cec03c3b67 eceeb89ddbaa44bb8fb5db2f935ae9fd - - -] Couldn't find multipath device /dev/mapper/360060160222044002bd07e5933aec3cb # virsh dumpxml instance-00000009 |grep disk <nova:disk>4</nova:disk> <disk type='block' device='disk'> <source dev='/dev/disk/by-path/pci-0000:81:00.0-fc-0x500009735018609f-lun-2'/> <alias name='virtio-disk0'/> </disk> <disk type='block' device='disk'> <source dev='/dev/disk/by-path/ip-192.168.0.1:3260-iscsi-iqn.1992-04.com.emc:cx.apm00xxxxxx-lun-1'/> <alias name='virtio-disk1'/> </disk>
From what we see, the problem is that the multipath doesn't create any of these 2 symlinks "/dev/mapper/<WWN>" or "/dev/disk/by-id/dm-uuid-mpath-<WWN>", which are the one os-brick is looking for. Although in coming releases in Ocata, os-brick will no longer use that mechanism to detect the multipaths. Once we test & pass this new package via the following bugs, you can confirm the new mechanism will work . https://bugzilla.redhat.com/show_bug.cgi?id=1484431 https://bugzilla.redhat.com/show_bug.cgi?id=1443612