openstack team mailing list archive

[Oleg Gelbukh <ogelbukh@xxxxxxxxxxxx>]

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@xxxxxxxxx> 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@xxxxxxxxxx
> > 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@xxxxxxxxxxxxxxxxxxx[mailto:
>> openstack-bounces+gabriel.hurley=nebula.com@xxxxxxxxxxxxxxxxxxx] *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@xxxxxx> 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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