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Hi Oleg,

Thank you for your investigation. Good lucky!

Can you let me know if find how to fix the bug?

Thanks,
Sam

On Wed, Aug 22, 2012 at 12:50 PM, Oleg Gelbukh <ogelbukh at mirantis.com>wrote:

> Hello,
>
> Is it possible that, during snapshotting, libvirt just tears down virtual
> interface at some point, and then re-creates it, with hairpin_mode disabled
> again?
> This bugfix [https://bugs.launchpad.net/nova/+bug/933640] implies that
> fix works on spawn of instance. This means that upon resume after snapshot,
> hairpin is not restored. May be if we insert the _enable_hairpin() call in
> snapshot procedure, it helps.
> We're currently investigating this issue in one of our environments, hope
> to come up with answer by tomorrow.
>
> --
> Best regards,
> Oleg
>
> On Wed, Aug 22, 2012 at 11:29 PM, Sam Su <susltd.su at gmail.com> wrote:
>
>> My friend has found a way to enable ping itself, when this problem
>> happened. But not found why this happen.
>> sudo echo "1" >
>> /sys/class/net/br1000/brif/<virtual-interface-name>/hairpin_mode
>>
>> I file a ticket to report this problem:
>> https://bugs.launchpad.net/nova/+bug/1040255
>>
>> hopefully someone can find why this happen and solve it.
>>
>> Thanks,
>> Sam
>>
>>
>> On Fri, Jul 20, 2012 at 3:50 PM, Gabriel Hurley <
>> Gabriel.Hurley at nebula.com> wrote:
>>
>>>  I ran into some similar issues with the _*enable*_hairpin() call. The
>>> call is allowed to fail silently and (in my case) was failing. I couldn’t
>>> for the life of me figure out why, though, and since I’m really not a
>>> networking person I didn’t trace it along too far.****
>>>
>>> ** **
>>>
>>> Just thought I’d share my similar pain.****
>>>
>>> ** **
>>>
>>> **-          **Gabriel****
>>>
>>> ** **
>>>
>>> *From:* openstack-bounces+gabriel.hurley=nebula.com at lists.launchpad.net[mailto:
>>> openstack-bounces+gabriel.hurley=nebula.com at lists.launchpad.net] *On
>>> Behalf Of *Sam Su
>>> *Sent:* Thursday, July 19, 2012 11:50 AM
>>> *To:* Brian Haley
>>> *Cc:* openstack
>>> *Subject:* Re: [Openstack] VM can't ping self floating IP after a
>>> snapshot is taken****
>>>
>>> ** **
>>>
>>> Thank you for your support.****
>>>
>>> ** **
>>>
>>> I checked the file  nova/virt/libvirt/connection.py, the sentence
>>> self._enable_hairpin(instance) is already added to the
>>> function  _hard_reboot().****
>>>
>>> It looks like there are some difference between taking snapshot and
>>> reboot instance. I tried to figure out how to fix this bug but failed. *
>>> ***
>>>
>>> ** **
>>>
>>> It will be much appreciated if anyone can give some hints.****
>>>
>>> ** **
>>>
>>> Thanks,****
>>>
>>> Sam****
>>>
>>> ** **
>>>
>>> On Thu, Jul 19, 2012 at 8:37 AM, Brian Haley <brian.haley at hp.com> wrote:
>>> ****
>>>
>>> On 07/17/2012 05:56 PM, Sam Su wrote:
>>> > Hi,
>>> >
>>> > Just This always happens in Essex release. After I take a snapshot of
>>> my VM ( I
>>> > tried Ubuntu 12.04 or CentOS 5.8), VM can't ping its self floating IP;
>>> before I
>>> > take a snapshot though, VM can ping its self floating IP.
>>> >
>>> > This looks closely related to
>>> https://bugs.launchpad.net/nova/+bug/933640, but
>>> > still a little different. In 933640, it sounds like VM can't ping its
>>> self
>>> > floating IP regardless whether we take a snapshot or not.
>>> >
>>> > Any suggestion to make an easy fix? And what is the root cause of the
>>> problem?****
>>>
>>> It might be because there's a missing _enable_hairpin() call in the
>>> reboot()
>>> function.  Try something like this...
>>>
>>> nova/virt/libvirt/connection.py, _hard_reboot():
>>>
>>>              self._create_new_domain(xml)
>>> +            self._enable_hairpin(instance)
>>>              self.firewall_driver.apply_instance_filter(instance,
>>> network_info)
>>>
>>> At least that's what I remember doing myself recently when testing after
>>> a
>>> reboot, don't know about snapshot.
>>>
>>> Folsom has changed enough that something different would need to be done
>>> there.
>>>
>>> -Brian****
>>>
>>> ** **
>>>
>>
>>
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>
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