----- Original Message ----- > From: "Laine Stump" <laine@xxxxxxxxx> > To: libvirt-users@xxxxxxxxxx > Cc: "Andrew Martin" <amartin@xxxxxxxxxxx> > Sent: Tuesday, January 14, 2014 3:54:51 AM > Subject: Re: Fake Network Interface > > On 12/30/2013 11:25 AM, Andrew Martin wrote: > > Is there a supported method for creating a fake network interface in a VM's > > configuration file? I was using the below construct, however it is no > > longer > > working for me in recent versions of libvirt (libvirt 1.0.2 with qemu-kvm > > 1.4.0). > > > I assume this wasn't working for you either because you previously had a > network named "fake" in your config, and that network wasn't present > when you tested with the newer libvirt, or because the <address> element > created a conflict with an existing device on the same guest that was > already using the same slot? > > > > Is there a different, preferred method for creating a fake virtual > > interface on the guest which does not exist on the host? > > <interface type='network'> > > <mac address='aa:aa:aa:aa:aa:aa'/> > > <source network='fake'/> > > <address type='pci' domain='0x0000' bus='0x00' slot='0x03' > > function='0x0'/> > > </interface> > > On 01/14/2014 12:54 AM, Andrew Martin wrote: > > I found the answer to this question: > > 1. create an XML file with a fake configuration (including a subnet not in > > use elsewhere): > > <network> > > <name>fake</name> > > <bridge name='virbr1' stp='on' delay='0' /> > > <ip address='192.168.0.1' netmask='255.255.0.0'></ip> > > </network> > > > 1) you don't need to (and probably shouldn't) specify the <bridge> > element when defining the new network - libvirt will autogenerate a > unique bridge name if one isn't provided, and stp defaults to on with a > delay of 0 anyway. > > 2) If this network is just a parking place, then you don't need to > specify an <ip> element either. This will save you from having an extra > dnsmasq instance started on the host to answer dns queries to > 192.168.0.1 (and has the added advantage that a guest will be unable to > use this "parked" network connection to erroneously communicate with the > host). > > In other words, all you really need in the XML file is this: > > <network> > <name>fake</name> > </network> > > > > > > 2. define the network: virsh net-define /path/to/fake.xml > > 3. autostart the network: virsh net-autostart fake > > 4. start the network now: virsh net-start fake > > > > Once done, you can add this block of XML to your VM config with "virsh edit > > <vm_name>": > > <interface type='network'> > > <mac address='aa:aa:aa:aa:aa:aa'/> > > <source network='fake'/> > > <address type='pci' domain='0x0000' bus='0x00' slot='0x03' > > function='0x0'/> > > </interface> > > Note that you should adjust the "slot" and "mac" arguments to avoid > > conflicts. > > > It's actually easier and less error prone to just omit the <mac> and > <address> elements completely - libvirt will auto-generate > non-conflicting values for both if they aren't provided. So the > interface xml would look like this: > > <interface type='network'> > <source network='fake'/> > </interface> > > (you may want to add a <model type='virtio'/> to use a better emulated > device than the default rtl8139). > Laine, Thanks for the suggestions on the best practices for how to do this. Andrew _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users
