[ovirt-users] Ovirt causing strange network issues?

[Derek Atkins]

On the host or in the guests?

-derek
Sent using my mobile device. Please excuse any typos.



On October 3, 2017 7:15:35 AM Colin Coe <colin.coe at gmail.com> wrote:

> Spanning Tree Protocol.
>
> Make sure the /etc/sysconfig/network-scripts/ifcfg-eth0 (or whatever) does
> not have an STP=yes line.
>
> CC
>
> On 3 Oct. 2017 19:11, "Derek Atkins" <derek at ihtfp.com> wrote:
>
>> I'm sorry. What is STP?
>> And how do I turn that off?
>>
>> -derek
>> Sent using my mobile device. Please excuse any typos.
>>
>> On October 2, 2017 7:41:15 PM Colin Coe <colin.coe at gmail.com> wrote:
>>
>>> Hi
>>>
>>> We saw something very similar to this a couple of years ago.  In our
>>> case, it was caused by STP being enabled on our hypervisors.
>>>
>>> HTH
>>>
>>>
>>>
>>> On 3 Oct. 2017 04:56, "Derek Atkins" <derek at ihtfp.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> I'm at my wits end so I'm tossing this here in the hopes that SOMEONE
>>>> will be able to help me.
>>>>
>>>> tl;dr: Ovirt is doing something on my network that is causing my fiber
>>>> modem to go from 3-5ms to 300-1000+ms round trip times.  I know it's
>>>> ovirt because when I unplug ovirt from my network the issue goes away;
>>>> when I plug it back in, the issue recurs.
>>>>
>>>> Long version:
>>>>
>>>> I've been running Ovirt 4.0.6 happily on CentOS 7.3 for several months
>>>> on a single host machine. Indeed, the host had an uptime of 200+ days
>>>> and was working great until approximately midnight, September 21/22
>>>> (just over a week ago).  I was on an airplane halfway across the
>>>> Atlantic at that time, so it wasn't anything I did.
>>>>
>>>> My network is configured as:
>>>>
>>>>   fiber modem <-> edgerouter <-> switch <-> everything else
>>>>
>>>> ovirt is living in the "everything else" area.
>>>>
>>>> When I sit with a laptop connected to either the everything else range
>>>> or even directly connected to the fiber modem, I run 'mtr' and see
>>>> network times (starting at the fiber modem) that bounce all over the
>>>> place.  When I unplug ovirt I see consistent 3-5ms times.  Plug it back
>>>> in, voom, back up to badness.
>>>>
>>>> I've spent several hours plugging and unplugging different devices
>>>> trying to isolate the issue.  The only "device" that has any effect is
>>>> my ovirt box.
>>>>
>>>> I have tried to debug this in several ways, but really the only thing
>>>> that seems to have helped at all is shutting down all the VMs and the
>>>> hosted engine.  Once nothing else is running (but the host itself), only
>>>> then does the network seem to return to normal.
>>>>
>>>> I'm really at my wits end on this; I have no idea what is causing this
>>>> or what might have changed to cause the issue right at that time.  I
>>>> also can't imagine what ovirt is doing over the network that could cause
>>>> the modem, two physical hops away, to lose its mind in this way.  But my
>>>> experiementation is definitely showing a direct correlation.
>>>>
>>>> Help!!
>>>>
>>>> -derek
>>>>
>>>> --
>>>>        Derek Atkins                 617-623-3745 <(617)%20623-3745>
>>>>        derek at ihtfp.com             www.ihtfp.com
>>>>        Computer and Internet Security Consultant
>>>> _______________________________________________
>>>> Users mailing list
>>>> Users at ovirt.org
>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>
>>>
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