nova boot fails when using rbd backend

[Jens Rosenboom]

Trace ends with:

TRACE nova.compute.manager [instance: c1edd5bf-ba48-4374-880f-1f5fa2f41cd3] File "/opt/stack/nova/nova/virt/libvirt/rbd.py", line 238, in exists
TRACE nova.compute.manager [instance: c1edd5bf-ba48-4374-880f-1f5fa2f41cd3] except rbd.ImageNotFound:
TRACE nova.compute.manager [instance: c1edd5bf-ba48-4374-880f-1f5fa2f41cd3] AttributeError: 'module' object has no attribute 'ImageNotFound'

It looks like the above module tries to do a "import rbd" and ends up importing itself again instead of the global library module.

A quick fix would be renaming the file to rbd2.py and changing the references in driver.py and imagebackend.py, but maybe there is a better solution?

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/111892

[OpenStack Infra (hudson-openstack)]

Change abandoned by Yaguang Tang (<email address hidden>) on branch: master
Review: https://review.openstack.org/111892

[Jens Rosenboom (frickler)]

As there seems to be some uncertainty as to whether this really is a bug:

I could reproduce this easily with a fresh VM running Ubuntu 14.04 and just the plain devstack setup from http://techs.enovance.com/6572/brace-yourself-devstack-ceph-is-here

To confirm the wrong module being loaded, I added a "print(rbd)" just after the import and got this in the log:

<module 'nova.virt.libvirt.rbd' from '/opt/stack/nova/nova/virt/libvirt/rbd.py'>

This may be specific to the way that devstack starts nova-compute.

[Daniel Berrange (berrange)]

I'm investigating why we're not seeing this in unit tests - a sign that we've got some missing scenario probably.

[Daniel Berrange (berrange)]

Strangely I'm not seeing a failure when I use devstack on 14.04 with the stack conf from that blog post

[Ivan Kolodyazhny (e0ne)]

I've got the same error with devstack+cinder+ceph

[Daniel Berrange (berrange)]

Oh, my devstack setup was messed up so it wasn't fully exercising RBD. Having fixed that I can reproduce the problem, so can try to figure out why our test suite don't see the same problem

[Ivan Kolodyazhny (e0ne)]

Daniel, thanks! I'll provide test for this issue if needed

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/111892
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=81348368c70cd39c6241e7da6d33629e577494f5
Submitter: Jenkins
Branch: master

commit 81348368c70cd39c6241e7da6d33629e577494f5
Author: Yaguang Tang <email address hidden>
Date: Tue Aug 5 11:06:10 2014 +0800

    Rename rbd.py to rbd_utils.py in libvirt driver directory

    In libvirt driver directory, rbd.py confict with global rbd library
    which is imported in rbd.py, so we rename rbd.py to rbd_utils.py.

    Change-Id: Ib62e430e678fe09c4a8475a636a8ecc11a194f5c
    Closes-Bug: #1352595

[Dmitry Borodaenko (angdraug)]

For the record, previous discussion of naming of this file:
https://review.openstack.org/#/c/94293/29/nova/virt/libvirt/ceph.py