Re: [libvirt-users] point-to-point connection between vm and host

Hello, we have been looking for other options to do this, and found that we can add qemu lines to the vm's xml for libvirt. What we want libvirt to do can be done with a qemu line like this: qemu -boot c -net nic,vlan=0,macaddr=02:fd:00:04:01:00,name=eth0 -net tap,vlan=0,ifname=ubuntu-e0,script=no ubuntu.img Which means that inside the host we connect a new tap device to the interface ubuntu-e0, and then connect the tap device of the host with the guest's nic, eth0. This provides connectivity between host and guest. The way to do this with libvirt seems with the tag <qemu:commandline>, which allows us to append some qemu lines. So now the definition file of the vm for libvirt looks like this: </domain> ...     <interface type="network" name="eth0" onboot="yes">       <source network="default"/>       <mac address="02:fd:00:04:01:00"/>     </interface> ...   <qemu:commandline>     <qemu:arg value="-net"/>     <qemu:arg value="nic,macaddr=02:fd:00:04:01:00"/>     <qemu:arg value="-net"/>     <qemu:arg value="tap,ifname=ubuntu-e0,script=no"/>   </qemu:commandline> </domain> With this, the guest shows the eth0 interface correctly configured. However there is no connectivity with the host. If we look at the log file, we find that some of the qemu options of the xml are missing, like the name oh the host's interface to be associated with the tap device ("ifname=ubuntu-e0"): # tail -f /var/log/libvirt/qemu/ubuntu.log LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-0.12 -cpu qemu32 -enable-kvm -m 256 -smp 1 -name ubuntu -uuid fb6e6954-53c6-7982-7b55-04edd406b871 -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/ubuntu.monitor,server,nowait -monitor chardev:monitor -boot cd -drive file=/root/.vnx/scenarios/simple_ubuntu/vms/ubuntu/fs/root_cow_fs,if=ide,index=0,boot=on,format=qcow2 -drive file=/root/.vnx/scenarios/simple_ubuntu/vms/ubuntu/fs/opt_fs.iso,if=ide,media=cdrom,index=1 -net nic,macaddr=02:fd:00:04:01:00,vlan=0,name=nic.0 -net tap,fd=16,vlan=0,name=tap.0 -net nic,macaddr=02:fd:00:04:01:01,vlan=1,name=nic.1 -net tap,fd=17,vlan=1,name=tap.1 -chardev pty,id=serial0 -serial chardev:serial0 -chardev socket,id=serial1,path=/root/.vnx/scenarios/simple_ubuntu/vms/ubuntu/ubuntu_socket,server,nowait -serial chardev:serial1 -parallel none -usb -vnc :1 -vga cirrus char device redirected to /dev/pts/8 What am i doing wrong? How can i specify the name of the host's interface? regards, Jorge On Wed, Apr 13, 2011 at 14:29, Jorge Somavilla <somavilla(a)dit.upm.es&gt; wrote: