Thank you for your comprehensive reply! On Tue, Sep 17, 2013 at 4:15 AM, Laine Stump <laine@xxxxxxxxx> wrote: > On 09/16/2013 07:34 PM, Ajith Antony wrote: >> The resulting ephemeral bridge(virbr1) looks like the following when my >> network(w/o vlans) and two domains are started. I don't know if the portgroup >> was meaningful, but it was accepted in the definition: >> >> $ sudo ovs-vsctl show >> <...> >> Bridge "virbr1" >> Port "vnet23" >> Interface "vnet23" >> Port "vnet25" >> Interface "vnet25" >> Port "virbr1" >> Interface "virbr1" >> type: internal >> Port "virbr1-nic" >> Interface "virbr1-nic" >> ovs_version: "1.9.3" > > > You apparently have openvswitch's "Linux host bridge compatibility" > package installed on your machine. If you didn't, the network definition > you have would have created a Linux host bridge rather than an > openvswitch bridge. libvirt doesn't contain any code that can create an > openvswitch bridge directly, so that's the only possible way this could > be happening. The problem is that when you use compatibility mode, > you're limited to the Linux bridge-utils API, which has no method of > specifying a vlan tag for individual ports (because Linux host bridges > lack that capability). Aha! I did not understand this. I was under the impression that libvirt was managing this. I understand now. >> Ultimately my goal is to prepare isolated test environments that consist of >> several VM's attached to a similar qty of vlans. I intend to create many of >> these environments per host. I also recongnize that instead of portgroups, I >> could use separate networks altogether. From an administrative standpoint, I'd >> prefer to have one "network" per test environment, with several portgroups, >> instead of *many* networks. > > > Since this is all just numbers in memory (no real cables / switches), > there is little to no practical difference between having a single > bridge with lots of vlans, or having lots of bridges with no vlans. > > One big difference is that you can do the latter today with existing > libvirt code (and you don't even need to have openvswitch installed on > your host). Unless you have > 255 guests on a single vlan, or need some > other openvswitch-specific feature not available with Linux host > bridges, I would just setup multiple networks and use the existing > libvirt networks. Yes, I'll probably go with the regular bridge behavior for now. One very attractive feature of using openvswitch is the ability to "re-wire" the whole set-up by reassigning the vlan tags on-the-fly. My base usecase should be consistent with the libvirt workflow, where things like changing domain interface configs take effect when a domain is destroyed and started again, but the opportunity to move interfaces around without a hard power-cycle could prove valuable. -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list