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On 07/29/2015 12:12 PM, NUNIN Roberto wrote: <br>
<font color="#000000">>> -----Messaggio originale----- </font><br>
<font color="#000000">>> Da: Michael S. Tsirkin [mailto:mst@<a href="mailto:redhat.com">redhat.com</a>] </font><br>
<font color="#000000">>> Inviato: mercoledì 29 luglio 2015 12:03 </font><br>
<font color="#000000">>> A: NUNIN Roberto </font><br>
<font color="#000000">>> Cc: Fabian Deutsch; users@<a href="mailto:ovirt.org">ovirt.org</a> </font><br>
<font color="#000000">>> Oggetto: Re: R: [ovirt-users] R: R: R: R: R: R: PXE boot of a VM on vdsm don't </font><br>
<font color="#000000">>> read DHCP offer </font><br>
<font color="#000000">>> </font><br>
<font color="#000000">>> On Wed, Jul 29, 2015 at 12:00:38PM +0200, NUNIN Roberto wrote: </font><br>
<font color="#000000">>>>> -----Messaggio originale----- </font><br>
<font color="#000000">>>>> Da: users-bounces@<a href="mailto:ovirt.org">ovirt.org</a> [mailto:users-bounces@<a href="mailto:ovirt.org">ovirt.org</a>] Per conto </font><br>
<font color="#000000">>> di </font><br>
<font color="#000000">>>>> Michael S. Tsirkin </font><br>
<font color="#000000">>>>> Inviato: giovedì 9 luglio 2015 15:15 </font><br>
<font color="#000000">>>>> A: Fabian Deutsch </font><br>
<font color="#000000">>>>> Cc: users@<a href="mailto:ovirt.org">ovirt.org</a> </font><br>
<font color="#000000">>>>> Oggetto: Re: [ovirt-users] R: R: R: R: R: R: PXE boot of a VM on vdsm don't </font><br>
<font color="#000000">>> read </font><br>
<font color="#000000">>>>> DHCP offer </font><br>
<font color="#000000">>>>> </font><br>
<font color="#000000">>>>> On Thu, Jul 09, 2015 at 08:57:50AM -0400, Fabian Deutsch wrote: </font><br>
<font color="#000000">>>>>> ----- Original Message ----- </font><br>
<font color="#000000">>>>>>> On Wed, Jul 08, 2015 at 09:11:42AM +0300, Michael S. Tsirkin wrote: </font><br>
<font color="#000000">>>>>>>> On Tue, Jul 07, 2015 at 05:13:28PM +0100, Dan Kenigsberg wrote: </font><br>
<font color="#000000">>>>>>>>> On Tue, Jul 07, 2015 at 10:14:54AM +0200, NUNIN Roberto wrote: </font><br>
<font color="#000000">>>>>>>>>>> On Mon, Jul 06, 2015 at 10:33:59AM +0200, NUNIN Roberto </font><br>
<font color="#000000">>> wrote: </font><br>
<font color="#000000">>>>>>>>>>>> Hi Dan </font><br>
<font color="#000000">>>>>>>>>>>> </font><br>
<font color="#000000">>>>>>>>>>>> Sorry for question: what do you mean for interface vnetxxxx ? </font><br>
<font color="#000000">>>>>>>>>>>> Currently our path is : </font><br>
<font color="#000000">>>>>>>>>>>> eno1 - eno2 ---- bond0 ----- bond.3500 (VLAN) ------ bridge ----- </font><br>
<font color="#000000">>>>>>>>>>>> vm. </font><br>
<font color="#000000">>>>>>>>>>>> </font><br>
<font color="#000000">>>>>>>>>>>> Which one of these ? </font><br>
<font color="#000000">>>>>>>>>>>> Moreover, reading Fabian statements about bonding limits, </font><br>
<font color="#000000">>>>> today I </font><br>
<font color="#000000">>>>>>>>>>>> can try </font><br>
<font color="#000000">>>>>>>>>>> to switch to a config without bonding. </font><br>
<font color="#000000">>>>>>>>>>> </font><br>
<font color="#000000">>>>>>>>>>> "vm" is a complicated term. </font><br>
<font color="#000000">>>>>>>>>>> </font><br>
<font color="#000000">>>>>>>>>>> `brctl show` would not show you a "vm" connected to a bridge. </font><br>
<font color="#000000">>>>> When </font><br>
<font color="#000000">>>>>>>>>>> you </font><br>
<font color="#000000">>>>>>>>>>> WOULD see is a vnet888 tap device. The "other side" of this </font><br>
<font color="#000000">>> device </font><br>
<font color="#000000">>>>> is </font><br>
<font color="#000000">>>>>>>>>>> held by qemu, which implement the VM. </font><br>
<font color="#000000">>>>>>>>>> Ok, understood and found it, vnet2 </font><br>
<font color="#000000">>>>>>>>>> </font><br>
<font color="#000000">>>>>>>>>>> I'm asking if the dhcp offer has reached that tap device. </font><br>
<font color="#000000">>>>>>>>>> No, the DHCP offer packet do not reach the vnet2 interface, I can </font><br>
<font color="#000000">>> see </font><br>
<font color="#000000">>>>>>>>>> only DHCP DISCOVER. </font><br>
<font color="#000000">>>>>>>>> Ok, so it seems that we have a problem in the host bridging. </font><br>
<font color="#000000">>>>>>>>> </font><br>
<font color="#000000">>>>>>>>> Is it the latest kernel-3.10.0-229.7.2.el7.x86_64 ? </font><br>
<font color="#000000">>>>>>>>> </font><br>
<font color="#000000">>>>>>>>> Michael, a DHCP DISCOVER is sent out of a just-booted guest, and </font><br>
<font color="#000000">>>>> OFFER </font><br>
<font color="#000000">>>>>>>>> returns to the bridge, but is not propagated to the tap device. </font><br>
<font color="#000000">>>>>>>>> Can you suggest how to debug this further? </font><br>
<font color="#000000">>>>>>>> Dump packets including the ethernet headers. </font><br>
<font color="#000000">>>>>>>> Likely something interfered with them so the eth address is wrong. </font><br>
<font color="#000000">>>>>>>> </font><br>
<font color="#000000">>>>>>>> Since bonding does this sometimes, this is the most likely culprit. </font><br>
<font color="#000000">>>>>>> We've ruled this out already - Roberto reproduces the issue without a </font><br>
<font color="#000000">>>>>>> bond. </font><br>
<font color="#000000">>>>>> To me this looks like either a regression in the host side bridging. But </font><br>
<font color="#000000">>> otoh it </font><br>
<font color="#000000">>>>> doesn't look </font><br>
<font color="#000000">>>>>> like it's happening always, because otherwise I'd expect more noise </font><br>
<font color="#000000">>> around </font><br>
<font color="#000000">>>>> this issue. </font><br>
<font color="#000000">>>>>> - fabian </font><br>
<font color="#000000">>>>> Hard to say. E.g. forwarding delay would do this for a while. </font><br>
<font color="#000000">>>>> If eth address of the packets is okay, poke at the fbd, maybe there's </font><br>
<font color="#000000">>>>> something wrong there. Maybe stp is detecting a loop - try checking that. </font><br>
<font color="#000000">>>> Someone is checking this ? </font><br>
<font color="#000000">>>> In tested config SPT was off. </font><br>
<font color="#000000">>> Then maybe you have a loop :) </font><br>
<font color="#000000">> That was already checked, the MAC was unique in the VLAN. </font><br>
<font color="#000000">> </font><br>
<font color="#000000">> RN </font><br>
<font color="#000000">> </font><br>
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Did you also try a reboot of the VM? We have the same issue with foreman <br>
and both Libvirt and oVirt. On second boot PXE boots properly from DHCP. <br>
<br>
Haven't had the time to investigate yet so we're using mostly image <br>
based provisioning on oVirt at the moment. <br>
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