Public bug reported:
Tested Environment
--
OS: Ubuntu 14.04 LST
Cinder NFS driver:
volume_driver=cinder.volume.drivers.nfs.NfsDriver
Error description
--
I used NFS as the cinder storage backend and successfully attached multiple
volumes to nova instances.
However, when I tried to detach one them, I found following error on
nova-compute.log.
2014-07-07 17:48:46.175 3195 ERROR nova.virt.libvirt.volume
[req-a07d077f-2ad1-4558-91fa-ab1895ca4914 c8ac60023a794aed8cec8552110d5f12
fdd538eb5dbf48a98d08e6d64def73d7] Couldn't unmount the NFS share
172.23.58.245:/NFSThinLun2
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume Traceback (most
recent call last):
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume File
/usr/local/lib/python2.7/dist-packages/nova/virt/libvirt/volume.py, line 675,
in disconnect_volume
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume
utils.execute('umount', mount_path, run_as_root=True)
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume File
/usr/local/lib/python2.7/dist-packages/nova/utils.py, line 164, in execute
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume return
processutils.execute(*cmd, **kwargs)
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume File
/usr/local/lib/python2.7/dist-packages/nova/openstack/common/processutils.py,
line 193, in execute
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume cmd='
'.join(cmd))
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume
ProcessExecutionError: Unexpected error while running command.
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume Command: sudo
nova-rootwrap /etc/nova/rootwrap.conf umount
/var/lib/nova/mnt/16a381ac60f3e130cf26e7d6eb832cb6
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume Exit code: 16
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume Stdout: ''
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume Stderr:
'umount.nfs: /var/lib/nova/mnt/16a381ac60f3e130cf26e7d6eb832cb6: device is
busy\numount.nfs: /var/lib/nova/mnt/16a381ac60f3e130cf26e7d6eb832cb6: device is
busy\n'
2014-07-07 17:48:46.175 3195 TRACE nova.virt.libvirt.volume
For NFS volumes, every time you detach a volume, nova tries to umount the
device path.
/nova/virt/libvirt/volume.py in
Line 632: class LibvirtNFSVolumeDriver(LibvirtBaseVolumeDriver):
Line 653: def disconnect_volume(self, connection_info, disk_dev):
Line 661: utils.execute('umount', mount_path, run_as_root=True)
This works when the device path is not busy.
If the device path is busy (or in use), it should output a message to log and
continue.
The problem is, Instead of output a log message, it raise exception and that
cause the above error.
I think the reason is, the ‘if’ statement at Line 663 fails to catch the device
busy massage from the content of the exc.message. It looking for the ‘target is
busy’ in the exc.message, but umount error code returns ‘device is busy’.
Therefore, current code skip the ‘if’ statement and run the ‘else’ and raise
the exception.
How to reproduce
--
(1) Prepare a NFS share storage and set it as the storage backend of you
cinder
(refer
http://docs.openstack.org/grizzly/openstack-block-storage/admin/content/NFS-driver.html)
In cinder.conf
volume_driver=cinder.volume.drivers.nfs.NfsDriver
nfs_shares_config=path to your nfs share list file
(2) Create 2 empty volumes from cinder
(3) Create a nova instance and attach above 2 volumes
(4) Then, try to detach one of them.
You will get the error in nova-compute.log “Couldn't unmount the NFS share
your NFS mount path on nova-compute”
Proposed Fix
--
I’m not sure about any other OSs who outputs the ‘target is busy’ in the umount
error code.
Therefore, first fix comes to my mind is fix the ‘if’ statement to:
Before fix;
if 'target is busy' in exc.message:
After fix;
if 'device is busy' in exc.message:
** Affects: nova
Importance: Undecided
Status: New
--
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https://bugs.launchpad.net/bugs/1340552
Title:
Volume detach error when use NFS as the cinder backend
Status in OpenStack Compute (Nova):
New
Bug description:
Tested Environment
--
OS: Ubuntu 14.04 LST
Cinder NFS driver:
volume_driver=cinder.volume.drivers.nfs.NfsDriver
Error description
--
I used NFS as the cinder storage backend and successfully attached multiple
volumes to nova instances.
However, when I tried to detach one them, I found following error on
nova-compute.log.
2014-07-07 17:48:46.175 3195 ERROR nova.virt.libvirt.volume
[req-a07d077f-2ad1-4558-91fa-ab1895ca4914 c8ac60023a794aed8cec8552110d5f12
fdd538eb5dbf48a98d08e6d64def73d7]
