[ovs-discuss] Set vnet to VM or alias to vnet

Ben Pfaff blp at nicira.com
Thu Sep 20 15:12:33 UTC 2012


Open vSwitch isn't assigning those "vnet numbers", by which it appears
you mean the name of a network device, and doesn't have control over
them.  If you want to use fixed names for them, then you will have to
do that through whatever does assign them.

On Thu, Sep 20, 2012 at 08:51:33AM +0200, r po wrote:
> 
> Hi,
> 
> I run openvswitch on Ubuntu and KVM. The vnet that i talk is the 'tap' on other distrib. The network interface for the VM. 
> Each VM has one or more network interface, we see there on hypervisor under the name : vnet (tap). Number for vnet is random (i guess .. ) and when i shutdown my VMs and reboot it, number's vnet (tap) is modified :  first VM start has vnet0, the 2nd vnet1. if i shutdown and restart the 2nd before the first then the 2nd has vnet0 and the first vnet1.
> If i look the cacti's graph then i must go on the hypervisor and see which VM attach to which Vnet at precise time  
> 
> Thanks
> 
> 
> > Date: Wed, 19 Sep 2012 10:32:49 -0700
> > From: blp at nicira.com
> > To: r2.d2 at live.fr
> > CC: discuss at openvswitch.org
> > Subject: Re: [ovs-discuss]  Set vnet to VM or alias to vnet
> > 
> > Can you tell me what you mean by a vnet number?  I do not know that
> > term.
> > 
> > On Wed, Sep 19, 2012 at 09:40:41AM +0200, r po wrote:
> > > 
> > > Hi, 
> > > 
> > > Thanks Ben for you answers on the bonding. It's really helpfull.
> > > 
> > > I have another question but not on the same part. I'd like to supervise my hypervisor (which hold my VM)
> > > with a cacti-like. It's works fine and i see all vnet, bridge and fake-bridge associate on the hypervisor.
> > > 
> > > But there's the problems : is it possible to set a vnet number to a VM or associate an alias ?
> > > i explain, when i stop many VM and reboot it but not in the same order, the vnet number will change (for each VM)
> > > so i got to reconfigure correctly my cacti-like for specify which vnet is for which VM and so which graph is for which VM. (or i must connect to hypervisor see which vnet is for which VM, it's not pratical .. )
> > > 
> > > it's possible to do this ? or implement ?
> > > 
> > > Thank's
> > > 
> > > Aeron
> > > 
> > > > Date: Tue, 18 Sep 2012 10:18:30 -0700
> > > > From: blp at nicira.com
> > > > To: r2.d2 at live.fr
> > > > CC: discuss at openvswitch.org
> > > > Subject: Re: [ovs-discuss] mode_bond balance-tcp and question
> > > > 
> > > > There is definitely a difference.  If you use balance-slb, then
> > > > streams from a particular host (that is, all streams, if you are not
> > > > using VMs) will use the same interface.  If you use balance-tcp, then
> > > > streams from a particular host will be spread (statistically) across
> > > > the available interfaces.
> > > > 
> > > > On Tue, Sep 18, 2012 at 07:20:08PM +0200, r po wrote:
> > > > > Ok ! Tanks a lot for this quickly answer that conforte me in my config.
> > > > > Can you explain me if there are à real difference on balance TCP and balance slb 
> > > > > If the choice is mostly random ?
> > > > > 
> > > > > Thanks again !
> > > > > 
> > > > > > Date: Tue, 18 Sep 2012 09:56:32 -0700
> > > > > > From: blp at nicira.com
> > > > > > To: r2.d2 at live.fr
> > > > > > CC: discuss at openvswitch.org
> > > > > > Subject: Re: [ovs-discuss] mode_bond balance-tcp and question
> > > > > > 
> > > > > > On Tue, Sep 18, 2012 at 04:35:08PM +0200, r po wrote:
> > > > > > > In the documentation i read, balance-tcp : balances among interface based on L2, L3 and L4 and MAC and IP.
> > > > > > > 
> > > > > > > But when i'm try to test the troughput (i used iperf) i don't up to 2Go on communication between two same IP witch two différent TCP port : 
> > > > > > > 
> > > > > > > here is my test : 
> > > > > > > 
> > > > > > > on ovs 1 : (i configured a fake bridge with IP, work well)
> > > > > > > 
> > > > > > > iperf -c 10.10.10.10 -p 1000 
> > > > > > > 
> > > > > > > (on other console but always in ovs1 )
> > > > > > > 
> > > > > > > iperf -c 10.10.10.10 -p 7000
> > > > > > > 
> > > > > > > on ovs2 (in two different console)
> > > > > > > 
> > > > > > > iperf -s -p 1000
> > > > > > > iperf -s -p 7000
> > > > > > > 
> > > > > > > i got about 500Mbps on each transfert.
> > > > > > 
> > > > > > The initial choice of interface for a given stream is essentially
> > > > > > random.  Every 10 seconds, streams get rebalanced.  If you have
> > > > > > exactly 2 streams, and each one lasts only a few seconds, whether you
> > > > > > see a benefit is a matter of luck.
> > > > >  		 	   		  
> > >  		 	   		  
> > 
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> > > discuss at openvswitch.org
> > > http://openvswitch.org/mailman/listinfo/discuss
> > 
>  		 	   		  

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