[ovs-discuss] Strange behaviour with VLANs and Bridges and ARP.

Blue Lang blue at veracity.io
Wed Aug 9 14:54:51 UTC 2017


The only place I've seen this is with VMWARE vswitch not forwarding ARP on
ESX. That doesn't sound like it's any part of your issue.

When you say "smart switch using openvswitch," what do you mean exactly?

Thanks,

On Tue, Aug 8, 2017 at 11:44 PM, Ricky <remsolutions2010 at gmail.com> wrote:

> I have run into a similar problem myself and have not found the solution.
> The ARP traffic from one direction makes it to OVS, but does not get sent
> to device it needs to go to. It my case OVS pretty much isn't sending any
> ARP packets out from itself except to the other OVS instances I have a GRE
> tunnel with. I'm running version 2.5.0.
>
> Please let me know if you made any progress on your issue.
>
>
> On 08/07/2017 07:19 PM, Schlacta, Christopher wrote:
>
>> Ping.  Anybody?  Hello?
>>
>> On Wed, Aug 2, 2017 at 10:32 PM, Schlacta, Christopher
>> <aarcane at aarcane.org> wrote:
>>
>>> So this is a bit hard to explain, but I hope you'll follow.  I have
>>> two hosts, density and densetsu.  they each host VMs and CEPH nodes
>>> using libvirt and ceph and they're connected to a smart switch using
>>> openvswitch and there are a bunch of VLANs.  5, 6, 10, 20, and 30.
>>> Most "normal" traffic goes along VLAN 10.  That's just the LAN VLAN.
>>> So here's what the ovs-vsctl show looks like on each host:
>>>
>>>
>>> density:
>>> aarcane at density:~$ sudo ovs-vsctl show
>>> YubiKey for `aarcane':
>>> f2ae0266-6cae-44f0-8ca5-9d6f66562ff4
>>>      Bridge "br0"
>>>          Port lan
>>>              tag: 10
>>>              Interface lan
>>>                  type: internal
>>>          Port "vnet0"
>>>              trunks: [5, 6, 10, 20, 30]
>>>              Interface "vnet0"
>>>          Port "eth1"
>>>              Interface "eth1"
>>>          Port "vnet1"
>>>              trunks: [5, 6, 10, 20, 30]
>>>              Interface "vnet1"
>>>          Port "br0"
>>>              Interface "br0"
>>>                  type: internal
>>>      ovs_version: "2.7.0"
>>>
>>>
>>> densetsu:
>>> aarcane at densetsu:~$ sudo ovs-vsctl show
>>> 2d6843ee-2bb6-48b8-a979-ba7f64bf5ebc
>>>      Bridge "br0"
>>>          Port "eth0"
>>>              Interface "eth0"
>>>          Port lan
>>>              tag: 10
>>>              Interface lan
>>>                  type: internal
>>>          Port "br0"
>>>              Interface "br0"
>>>                  type: internal
>>>      ovs_version: "2.7.0"
>>>
>>>
>>> The problem is when I try to ping the opposite machine (densetsu to
>>> density or vice versa), the ARP packets get sent with appropriate
>>> information through BR0 and out the eth device all tagged with VLAN
>>> 10, but the *inbound* arp packet is never sent to the lan interface.
>>> I see it at the br0 and the eth interface, but not the destination
>>> host's lan interface.  Furthermore, the destination never seems to see
>>> this or respond to it, so it's then impossible for the to initiate
>>> contact without adding entries to the ethers file.
>>>
>>> This is well and good, but it also means that other systems on the
>>> network also cannot connect to them for purposes of administration and
>>> management, and this is very problematic.
>>>
>>> I've not made any changes to openflow.  They've been able to
>>> communicate with each other for a long time.  This change happened
>>> with a recent kernel upgrade.  Not sure how to fix it or if it's a
>>> bug.  Again, note:  All IP traffic seems to work fine.  ICMP works
>>> without issue, TCP, etc.  It's only the ARP protocol that seems to not
>>> be passing inward when it should be.
>>>
>> _______________________________________________
>> discuss mailing list
>> discuss at openvswitch.org
>> https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
>>
>
>
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-- 
Blue Lang
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