Missing exception data for exceptions raised in floating ip assignment when ebtables is missing

[Nick Moffitt]

When I tried to assign one of my successfully-allocated floating IPs to one of my instances, my nova-network.log showed this rather unhelpful traceback: http://paste.openstack.org/show/40674/

I'm running nova-network 1:2013.1.2-0ubuntu1~cloud0 from the cloud archive, on Ubuntu 12.04 LTS.

My searches through bugs while trying to find the *real* error turned up bug#1119817 which seems to be of a type with this one (although apparently more thoroughly researched).

[Nick Moffitt (nick-moffitt)]

Okay, I"ve tracked this down to:

2013-07-17 12:44:34.849 12414 TRACE nova.api.openstack.compute.contrib.floating_ips File "/usr/lib/python2.7/dist-packages/nova/network/floating_ips.py", line 375, in do_associate
2013-07-17 12:44:34.849 12414 TRACE nova.api.openstack.compute.contrib.floating_ips raise
2013-07-17 12:44:34.849 12414 TRACE nova.api.openstack.compute.contrib.floating_ips TypeError: exceptions must be old-style classes or derived from BaseException, not NoneType

And making line 375 of that file say "raise e" instead of just a bare raise gets me this:

2013-07-17 12:50:59.518 12414 TRACE nova.api.openstack.compute.contrib.floating_ips ProcessExecutionError: Unexpected error while running command.
2013-07-17 12:50:59.518 12414 TRACE nova.api.openstack.compute.contrib.floating_ips Command: sudo nova-rootwrap /etc/nova/rootwrap.conf ebtables -t nat -I PREROUTING --logical-in br3812 -p ipv4 --ip-src 10.55.224.3 ! --ip-dst 10.55.224.0/29 -j redirect --redirect-target ACCEPT
2013-07-17 12:50:59.518 12414 TRACE nova.api.openstack.compute.contrib.floating_ips Exit code: 96
2013-07-17 12:50:59.518 12414 TRACE nova.api.openstack.compute.contrib.floating_ips Stdout: '/usr/bin/nova-rootwrap: Executable not found: /sbin/ebtables (filter match = ebtables)\n'
2013-07-17 12:50:59.518 12414 TRACE nova.api.openstack.compute.contrib.floating_ips Stderr: ''

So this is a problem in my deployment, but the error handling isn't helping me work it out right now. I'll update the subject to be more specific.

[Russell Bryant (russellb)]

https://review.openstack.org/#/c/45750/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/45750
Committed: http://github.com/openstack/nova/commit/3e1e2448bf162bd2750416efe5d7c1010b51b52a
Submitter: Jenkins
Branch: master

commit 3e1e2448bf162bd2750416efe5d7c1010b51b52a
Author: Russell Bryant <email address hidden>
Date: Mon Sep 9 16:14:38 2013 -0400

    Don't lose exception info

    Using eventlet introduces some extra fun into exception handling. After
    catching an exception, it is required to save off the exception details
    if you want to be able to re-raise it later after doing other operations
    which may do a greenthread switch. That's what this patch does. It
    saves off the original exception that we intend to re-raise later and
    ensures that nothing stomps on it in the meantime.

    A test case was also added to exercise this code path to make sure the
    exception saving and re-raising worked as expected.

    Change-Id: Ibf5f06a30839b93ece500ce7dbb714f6509f85af
    Closes-bug: #1202177