[ovs-discuss] question about creating Ethernet switches in VMs (on single physical machine)

[Justin Pettit]

Based on your diagram, I'd think you'd want to run OVS inside VM2.  This would be configured as you described with those ovs-vsctl commands.

However, this seems like a fairly non-standard setup.  Usually, the networking is managed in the hypervisor, so VM1 and VM3 would just be wired up to OVS running there.  But I may not understand what you're trying to do...

--Justin


On May 30, 2012, at 10:46 PM, Dong Jin wrote:

> I am new to openvswitch and openflow. I setup the following scenario
> on a single physical machine:
> 
> VM1(veth1.0)  -------  (veth2.0) VM2 (veth2.1)  --------- (veth3.0) VM3
> 
> VM1 and VM3 are two end-hosts. VM3 is to emulate an Ethernet switch.
> VM2 should be controlled by ovs-vswitchd (possibly with the POX
> controller later).
> 
> After going through the ovs-vswitchd.conf.db(5), here is my
> understanding (correct me if I am wrong): The single ovs-vswitchd
> manages a set of bridges (i.e. Ethernet switches), each bridge has a
> set of ports (i.e. Ethernet interfaces).
> 
> It looks that ovs-vswitchd should run outside any VMs, and it creates
> br0 which represents the Ethernet switch.
> ovs-vsctl add-br br0
> ovs-vsctl add-port br0 veth2.0
> ovs-vsctl add-port br0 veth2.1
> 
> I am a little bit confused here. I original thought there should be a
> program running  (or at least something stored) in VM2 so that VM2 can
> emulate an Ethernet switch. It looks that the bridge representing the
> switch is created outside VMs. So if I want to emulate 10 switches,
> does that mean all the flow tables are stored and managed in a central
> place outside VMs? If so, what is the usage of having VM2 here?
> 
> I know mininet uses openvswitch and VMs (they use linux container) are
> created for Ethernet switch respectively. I think I probably
> misunderstand something here. Could someone kindly advise?
> 
> thanks in advance.
> 
> kevin
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