Did some further refining and testing on this. I found that all that needed to be done to create a NAT or private network for your ovirt guests is (in this example we create a NAT network): 1) Login into your ovirt nodes (all will need to have this created consistently across them. 2) connect to qemu/libvirt with "virsh" 3) virsh# connect qemu:///system 4) username is: vdsm@rhevh 5) password is found in the file /etc/pki/vdsm/keys/libvirt_password 6) Create a network xml definition like so (in this example NAT): <network> <name>nat</name> <uuid>b09d09a8-ebbd-476d-9045-e66012c9e83d</uuid> <forward mode='nat'/> <bridge name='natbr0' stp='on' delay='0' /> <mac address='52:54:00:9D:82:DE'/> <ip address='192.168.1.1' netmask='255.255.255.0'> <dhcp> <range start='192.168.1.2' end='192.168.1.250' /> </dhcp> </ip> </network> 7) Save the network definition at /etc/libvirt/qemu/networks (EX: /etc/libvirt/qemu/networks/nat.xml) 8) Add the network: virsh# net-define /etc/libvirt/qemu/networks/nat.xml) 9) Set the network to autostart: virsh# net-autostart nat.xml 10) If this is NAT you will need to enable packet forwarding in /etc/sysctl.conf (EG: set net.ipv4.ip_forward = 1) 11) If you don't want the reboot the host for this to take effect do: echo '1' > /proc/sys/net/ipv4/ip_forward 12) In the ovirt UI select the cluster which contains the hosts on which you created the network 13) Create a new logical network with the same name as the bridge name element from the above xml.(EX: natbr0) 14) Remember to enable STP in this case since this is a private or NAT network 15) The logical network will be show as non-operational, so we will need to manually online the network. --> vdsm/ovirt network creation seems to be tied to host physical interfaces and does not look at virtual interfaces in this case vdsm kicks in and finds natbr0 and consequently creates vdsm-natbr0 and natbr0-nic but does nothing more to report it back to the ovirt engine. (ovirt developers feel free to comment on this...) 16) Thus since ovirt does not detect that natbr0 exists and is actually online we need to make a quick database modification to force it online so it can actually be used. 17) We first need to find out the UUID of natbr0 interface 18) type the following: psql -U postgres engine -c "SELECT network.id FROM public.network WHERE network.name = '<natbr0';" (remember to substitute the name you used for the network) 20) This returns you the UUID of the network 21) Next we need to online the network now that we know it's UUID 22) type the following: psql -U postgres engine -c "update network_cluster set status='1' where network_id='<the network uuid returned from the previous command goes here>';" 23) You should now be able to attach guest vnics to your newly created NAT or private network. oVirt developers, any hope of getting this supported officially as part of ovirt? It seems like it would be relatively easy since the functionality exists in libvirt, and vdsm seems to be aware but the hooks into the engine/UI are what seem to be missing. - DHC On Mon, Apr 23, 2012 at 4:49 PM, Dead Horse <deadhorseconsulting(a)gmail.com&gt;wrote: