[ovs-discuss] Re : OVS and KVM: getting persistent UUID's or querying UUID values based on interface name

Sean Brady sbrady at gtfservices.com
Thu Jul 1 22:50:29 UTC 2010

Nevermind, I didn't see Justin's answer to all my questions.  Sorry all.

On 07/01/2010 04:44 PM, Sean Brady wrote:
> Hey, I see commit f40a9b6 addressing the UUID issue.  Thanks!  Are we 
> looking for another release tag anytime soon?  Looks like quite a bit 
> of activity and fine tuning in the commit logs.
> This is turning out to be quite a fascinating piece of software for me...
> Thanks all.
> On 07/01/2010 12:13 AM, Sean Brady wrote:
>> Short answer- your second option in your question.  I should have 
>> worded that better.  (and if you can think of a better way to do 
>> this, please let me know)
>> My test setup in more detail:
>> On the KVM host (hypervisor005), I have 3 physical interfaces: eth0, 
>> eth1, eth2.  eth0 is for the KVM host itself, eth1 is for guest VM's 
>> to communicate with the rest of the LAN, and eth2 is solely for 
>> SPAN.  My physical switch is set to output SPAN on the port that eth2 
>> is connected to.
>> Also on the KVM host I have 2 bridges configured with OVS: br0 and br1.
>> My VM has 2 interfaces: eth0 and eth1, which are vnet0 and span0 on 
>> the KVM host, respectively.  eth0 is for host communication (VM guest 
>> communication in relation to the KVM host) and eth1 is for "sniffing".
>> [root at hypervisor005 ~]# ovs-vsctl list-ports br0
>> eth1
>> vnet0
>> [root at hypervisor005 ~]# ovs-vsctl list-ports br1
>> eth2
>> span0
>> On 06/30/2010 07:15 AM, DarkBls wrote:
>>> Are you saying that a VM interface (tap0 for exemple) are connected 
>>> to both bridge or you have a tap0 on the bridge dedicated to guest 
>>> network and a tap1 on the bridge dedicated for SPAN monitor ?
>>> ----- Message d'origine ----
>>> De : Sean Brady <sbrady at gtfservices.com>
>>> À : "discuss at openvswitch.org" <discuss at openvswitch.org>
>>> Envoyé le : Mer 23 juin 2010, 21h 29min 48s
>>> Objet : [ovs-discuss] OVS and KVM: getting persistent UUID's or 
>>> querying UUID values based on interface name
>>> Hello all,
>>> I am trying to implement a SPAN port in combination with a KVM guest 
>>> as a SPAN monitor.  I have two bridges set up, one for guest network 
>>> and the other for the SPAN port, in conjunction with a dedicated NIC 
>>> port for each bridge (eth1 for guest networking and eth2 for SPAN).  
>>> I have the physical switch connected to eth2 sending SPAN output to 
>>> this dedicated network port (eth2).  I have it working by using 
>>> modifying the OVS database's mirror table to mirror traffic from the 
>>> dedicated SPAN NIC to the virtual port connected to the VM.
>>> In KVM when a VM is shutdown, the virtual interface is deleted, and 
>>> when the VM is started back up, a new interface is created by 
>>> libvirt and added to (both) bridges.  The issue is that when the new 
>>> interface is created, it gets a new UUID, which of course will need 
>>> to be added back into the mirror table as the output_port.
>>> Is there any way to get UUID persistence for these virtual 
>>> interfaces?  If not, is there a clean way to query the DB to get the 
>>> UUID of a named port?  If I could just consistently get the UUID of 
>>> the port using a shell script I can have this working when the VM is 
>>> started up.
>>> Thanks for your help.
>>> -Sean
>>> P.S.: I am working on documenting this out, as well as my steps for 
>>> using bridging with OVS and KVM.  If we decide it's helpful I am 
>>> more than happy to contribute it.
>>> _______________________________________________
>>> discuss mailing list
>>> discuss at openvswitch.org <mailto:discuss at openvswitch.org>
>>> http://openvswitch.org/mailman/listinfo/discuss_openvswitch.org
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