Comment 4 for bug 822748

A) Do you know if multi-master sql supports row locking?

B) Can you switch to the carrot driver for rpc and see if you still see the error:
--rpc_backend=nova.rpc.impl_carrot

On Nov 17, 2011, at 4:18 AM, Tom Ellis wrote:

> I should also mention that RabbitMQ is controlled by Pacemaker and at the moment there is only one compute node.
> I only really see it when I fire off multiple instances at once. If I run euca-run-instances sequentially, it copes fine but when running 'euca-run-instances -n 3', I see this error and the instances fail to launch.
>
> --
> You received this bug notification because you are subscribed to
> OpenStack Compute (nova).
> https://bugs.launchpad.net/bugs/822748
>
> Title:
> exceptions must be old-style classes or derived from BaseException,
> not NoneType
>
> Status in OpenStack Compute (Nova):
> Fix Released
>
> Bug description:
> Sometime recently, many exceptions in nova are resulting in a
> traceback similar to this:
>
> (nova): TRACE: Traceback (most recent call last):
> (nova): TRACE: File "/usr/lib/pymodules/python2.6/nova/rpc/amqp.py", line 230, in _process_data
> (nova): TRACE: rval = node_func(context=ctxt, **node_args)
> (nova): TRACE: File "/usr/lib/pymodules/python2.6/nova/exception.py", line 125, in wrapped
> (nova): TRACE: raise
> (nova): TRACE: TypeError: exceptions must be old-style classes or derived from BaseException, not NoneType
> (nova): TRACE:
>
> This appears to be an unrelated problem that is obscuring the real
> exception and makes it difficult to troubleshoot other problems.
>
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