[ovs-dev] OVS and namespaces

Jesse Gross jesse at nicira.com
Tue Oct 9 16:02:28 UTC 2012

On Tue, Oct 9, 2012 at 4:25 AM, Gary Kotton <gkotton at redhat.com> wrote:
> On 10/08/2012 10:24 PM, Jesse Gross wrote:
>> On Sat, Oct 6, 2012 at 10:21 AM, Gary Kotton<gkotton at redhat.com>  wrote:
>>> Hi,
>>> When Quantum is using OVS and namespaces there are problems when
>>> namespace
>>> is being deleted. More specifically this is when a default gateway is
>>> assigned to an interface that is used by the OVS. A simple way of
>>> reproducing this is:
>>> sudo ip netns exec<name>   ip route del ...
>>> sudo ip netns exec<name>   ovs-vsctl del-port...
>>>  From this moment on one is not able to access the namespace. The problem
>>> does not occur when the traditional linux bridges are used.
>>> Has anyone encountered this before?
>> I haven't heard of it before and can't think of any reasons why it
>> might be the case.  I tried reproducing it as well but couldn't
>> although I'm not sure that I understand what you mean by not being
>> able to access the namespace.
>> Can you give a more detailed set of steps of how to reproduce this and
>> more information about your environment (like the kernel version)?
> Hi,
> Sorry for being a bit vague in the description. The problem occurs when
> running OVS with Quantum and namespaces are enabled (this is the default).
> It is very easy to reproduce. I have done this one Ubuntu 12.04, Fedora 17
> and Fedora 18. The easiest way of reproducing is to make use of devstack.
> (www.devstack.org)
> Reproduction steps:
> 1.  git clone git://github.com/openstack-dev/devstack.git
> 2. Add the following to the file - stackrc
> ENABLED_SERVICES+=q-svc,quantum,q-agt,q-dhcp,q-l3
> Q_PLUGIN=openvswitch
> 3. ./stack.sh
> This launches openstack with OVS. The installtion will create 2 namespaces.
> The first for the dhcp service and the second for the layer 3 agent.
> You can then run ' nova boot --image cirros-0.3.0-x86_64-uec --flavor 1 t1'
> to launch a VM.
> Once this is done you can try and delete the namespaces and you will see the
> problem.
> Alternativey you can take a look at -
> https://fedoraproject.org/wiki/Test_Day:2012-09-18_OpenStack and the link
> https://fedoraproject.org/wiki/QA:Testcase_Quantum_V2

Can you please try to narrow the set of steps down to those that
actually involve OVS without OpenStack?  I'm having a hard time
imagining something in OVS causing the problem that you're describing
(and I couldn't reproduce it) so my suspicion is that it's something
in the way that OpenStack uses OVS rather than OVS itself.

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