Re: [libvirt] Notes on configuring Open vSwitch, Linux bridge and Libvirt

On 07/12/2013 06:32 PM, Daniel P. Berrange wrote: > On Fri, Jul 12, 2013 at 05:51:14PM +0530, Kashyap Chamarthy wrote: >> Heya Laine, >> >> Here's some quick notes to associate libvirt guests to Open vSwitch. >> >> Configure Open vSwitch >> ---------------------- >> >> Now that a regular Linux bridge is configured, let's try to configure an >> OVS brdige and get IP addresses from that space: >> >> Create an Open vSwitch bridge device called 'ovsbr', and display the >> current state of OpenvSwitch database contents: >> >> $ ovs-vsctl add-br ovsbr >> $ ovs-vsctl show >> >> >> Add a virtual ethernet interface called 'veth0' with >> >> $ ip link add name veth0 \ >> type veth peer name veth1 >> >> Add 'veth0' ethernet device to the Linux bridge 'br0', and enumerate all >> bridge devices: >> >> $ brctl addif br0 veth0 >> $ brctl show > > I don't really see why you are linking ovs to a traditional software > bridge. I had no specific reason on mind. The only test machine I had free was already having a Linux bridge. I thought I'd try on it anyway. Meanwhile, from this networking notes page, http://docs.openstack.org/trunk/openstack-network/admin/content/under_the... it appears that OpenStack uses Linux bridge in conjunction with an OVS bridge: There are four distinct type of virtual networking devices: TAP devices, veth pairs, Linux bridges, and Open vSwitch bridgesFor an ethernet frame to travel from eth0 of virtual machine vm01, to the physical network, it must pass through nine devices inside of the host: TAP vnet0, Linux bridge qbrXXX, veth pair (qcbXXX, qvoXXX), Open vSwitch bridge br-int, veth pair (int-br-eth1, phy-br-eth1), and, finally, the physical network interface card eth1.