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Re: irregular but frequent networking issues (Essex on Ubuntu 12.04)

 

Hi Cris, maybe your problem is related to this bug ?

https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/997978

Regards.
Ale


On Fri, Oct 5, 2012 at 8:44 AM, Christian Parpart <trapni@xxxxxxxxx> wrote:

> Hey all,
>
> we're pretty happy about our new OpenStack Essex installation atop of
> Ubuntu 12.04 (hypervisor and guests).
> We use KVM (tenant is in a VLAN) as virtualization technology, having
> about 15 compute nodes, and a
> central nova-network node to act as the gateway (yet to be fully HA'd,
> however). On that gateway we're having
> a PPTP VPN so we can log in on any host or guest though this VPN.
>
> Our problem however is, that from time to time (I think it's daily and
> even multiple times per day)
> we're encountering kind of networking freezes.
>
> I first noticed it as my SSH session froze for a few seconds from my
> desktop -> VPN (nova-network node) -> KVM guest.
> I quickly checked others, and they hang, too.
> I checked a hypervisor, which didn't hang, so it is not a general
> networking issue (like PPTP or SSH or alike).
>
> Now, it feels like there is some problem with networking from and/or to
> KVM guests and I absolutely have no clue
> on how to trace this down. It really feels like a bug, but that's really
> out of my scope, and that's why I'm seeking for advice here,
> since we just can't stay in this situation :-)
>
> It is confirmed that we're having this from desktop -> VPN -> KVM and from
> physical node (in data center) to KVM.
> However, I do not yet know whether all KVMs are affected at once (which
> would indicate that the issue MAY be caused
> by the central nova-network node) or whether it is just hypervisor based
> (so it may be due to some hypervisor's state)
> or just plain random across all 15 compute nodes we have.
>
> I now think that this issue may indeed be KVM networking related
>
> I'll be happy about any hints and proposals you can provide me in order to
> track this
> issue down.
>
> Please tell me about any further information you need.
>
> Many thanks in advance,
> Christian Parpart.
>
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