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Sorry for jumping into the discussion, but I'm currently experiencing exactly the opposite behaviour.
<div>DHCP offer is reached until the host bridge interface, but it is not propagated to the vnet device.</div>
<div>I'm using VLAN tagging. Packets incoming are correctly managed until vnet device and seems to have impact only into DHCP packets.</div>
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</div>
<div>Static IP assigned to the vm åeave VM active and reachable.</div>
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<div>Just my cent to a topic that I suppose could be related to mine issue.</div>
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<div>Roberto</div>
<br>
<br>
-------- Messaggio originale --------<br>
Da: Felix Pepinghege <pepinghege@ira.uka.de> <br>
Data: 17/08/2015 13:36 (GMT+01:00) <br>
A: Users@ovirt.org <br>
Oggetto: Re: [ovirt-users] vlan-tagging on non-tagged network <br>
<br>
<font size="2">
<div class="PlainText">Hi Ido, hi everybody,<br>
<br>
sorry that I kept you waiting for two months, I only just found the time <br>
to go back to this problem.<br>
<br>
You were completely right with your guess. The ethernet frames do appear <br>
on the vnet-interface, but not on the bridge. The dropped-counter seems <br>
to be independent from these losses, though.<br>
<br>
However, while this tells me *where* the problem is, I still don't know <br>
*what* the problem is. I've done some research, but couldn't find <br>
anything particularly helpful.<br>
An interesting point may be that this problem is mono-directional. That <br>
is, the bridge happily passes vlan-tagged frames from the ethernet <br>
device to the vnet, but not the other way around. Untagged ethernet <br>
frames make their way through the brigde, no matter where they come from.<br>
<br>
The vlan module is loaded, as to the versioning questions:<br>
# cat /etc/centos-release ; uname -s -v -r<br>
CentOS Linux release 7.1.1503 (Core)<br>
Linux 3.10.0-229.7.2.el7.x86_64 #1 SMP Tue Jun 23 22:06:11 UTC 2015<br>
<br>
The guest OS is an up-to-date Debian Jessie, which should not matter, <br>
though, as the frames get lost on the doorstep of the bridge on the host.<br>
<br>
Again, any suggestions are much appreciated!<br>
<br>
Regards,<br>
Felix<br>
<br>
<br>
Am 16.06.2015 um 08:27 schrieb Ido Barkan:<br>
> Hey Felix.<br>
><br>
> IIUC your frames are dropped by the bridge. Ovirt uses Linux Bridges<br>
> To connect virtual machines to 'networks'. The guest connects to the bridge<br>
> using a tap device which usually is called 'vnet<number>'.<br>
><br>
> So, just to verify, can you please tcpdump both on the bridge device and on the tap device?<br>
> The bridge can be quite noisy so I suggest filtering traffic using the guest's MAC<br>
> address. So I am not sure what protocol you use for tunneling but applying<br>
> a filter similar to this one should do the job:<br>
> tcpdump -n -i vnet0 -vvv -s 1500 'udp[38:4]=0x001a4aaeec8e'<br>
><br>
> My guess is that you will observe traffic on the tap device, but not on the bridge.<br>
> You didn't specify which centOS version you use but I do remember seeing people<br>
> complaining about Linux bridges discarding their tagged frames.<br>
> You can -maybe- also observe the 'dropped' counter increases on the bridge by running:<br>
> 'ip -s link show dev trunk'<br>
><br>
> There were a few bugs on rhel6/7 about this, specifically I remember<br>
> <a href="https://bugzilla.redhat.com/show_bug.cgi?id=1174291">https://bugzilla.redhat.com/show_bug.cgi?id=1174291</a><br>
> and<br>
> <a href="https://bugzilla.redhat.com/show_bug.cgi?id=1200275#c20">https://bugzilla.redhat.com/show_bug.cgi?id=1200275#c20</a><br>
><br>
> Also, is the vlan module loaded on your host?<br>
> 'lsmod |grep 8021q'<br>
><br>
> Thanks,<br>
> Ido<br>
><br>
> ----- Original Message -----<br>
> From: "Felix Pepinghege" <pepinghege@ira.uka.de><br>
> To: Users@ovirt.org<br>
> Sent: Monday, June 15, 2015 11:33:39 AM<br>
> Subject: [ovirt-users] vlan-tagging on non-tagged network<br>
><br>
> Hi everybody!<br>
><br>
> I am experiencing a behaviour of ovirt, of which I don't know whether it<br>
> is expected or not. My setup is as follows:<br>
> A virtual machine has a logical network attached to it, which is<br>
> configured without vlan-tagging and listens to the name 'trunk'.<br>
> The VM is running an openvpn server. It is a patched openvpn version,<br>
> including vlan-tagging. That is, openvpn clients get a vlan tag. This<br>
> should not really be an issue but should satisfy the "why do you want to<br>
> do it in the first place"-questions.<br>
> Anyhow, effectively, the VM simply puts vlan-tagged ethernet-frames on<br>
> the virtual network. These frames, however, never make it to the host's<br>
> network bridge, which represents the logical network.<br>
> My observations are: According to tcpdump, the vlan-tagged packages<br>
> arrive at the "eth1"-interface inside the VM (which *is* the correct<br>
> interface). Again, according to tcpdump, these packages never arrive at<br>
> the corresponding network-bridge (i.e., the interface 'trunk') on the host.<br>
> I know that the setup itself is feasible with KVM---I have it working on<br>
> a proxmox-machine. Therefore, my conclusion is, that ovirt doesn't like<br>
> vlan-tagged ethernet-frames on non-tagged logical networks, and somehow<br>
> filters them out, though I don't really see on what "level" that would<br>
> happen (Handling the ethernet frames should be a concern of<br>
> KVM/QEMU/Linux only, once ovirt has started the VM).<br>
> So this problem could be a CentOS issue, but I really don't see why<br>
> CentOS should act differently than debian does (proxmox is debian-based).<br>
> Is this a known/wanted/expected behaviour of ovirt, and can I somehow<br>
> prevent or elude it?<br>
><br>
> Any help is much appreciated! Of course I am happy to provide more<br>
> information if that helps helping me :)<br>
><br>
> Regards,<br>
> Felix<br>
> _______________________________________________<br>
> Users mailing list<br>
> Users@ovirt.org<br>
> <a href="http://lists.ovirt.org/mailman/listinfo/users">http://lists.ovirt.org/mailman/listinfo/users</a><br>
><br>
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