Fedora 17 : KVM : use macvtap

[root@fc17 ~]# qemu-kvm --version QEMU emulator version 1.0 (qemu-kvm-1.0), Copyright (c) 2003-2008 Fabrice Bellard [root@fc17 ~]# libvirtd --version libvirtd (libvirt) 0.9.11.4 [root@fc17 ~]# uname -ri 3.4.4-5.fc17.x86_64 x86_64 [root@fc17 ~]# cat /etc/fedora-release Fedora release 17 (Beefy Miracle) [root@fc17 ~]#

what’s macvtap ?
http://www.linux-kvm.com/content/simple-bridged-networking-virt-manager-using-macvtap

In brief , you can easily configure VM’s network as a bridge mode.
You can also use VEPA , short for  Virtual Ethernet Port Aggregator
( http://wikibon.org/wiki/v/Edge_Virtual_Bridging#Virtual_Ethernet_Port_Aggregator_.28VEPA.29 )

To use macvtap , your KVM host needs to load macvtap and macvlan modules.

# lsmod | grep tap macvtap                18240  1 vhost_net macvlan                18656  1 macvtap

edit VM’s xml file.

[root@fc17 ~]# virsh Welcome to virsh, the virtualization interactive terminal. Type:  'help' for help with commands       'quit' to quit virsh # list --all Id    Name                           State ---------------------------------------------------- -     f16-1                          shut off virsh # edit f16-1

before

<domain type='kvm'>  <name>f16-1</name>  <uuid>6de2733a-f21f-c04f-baec-2f79f7ff45e2</uuid>  <memory unit='KiB'>262144</memory>  <currentMemory unit='KiB'>262144</currentMemory>  <vcpu current='1'>2</vcpu>  <os>    <type arch='x86_64' machine='pc-0.15'>hvm</type>    <boot dev='hd'/>  </os>  <features>    <acpi/>    <apic/>    <pae/>  </features>  <clock offset='utc'/>  <on_poweroff>destroy</on_poweroff>  <on_reboot>restart</on_reboot>  <on_crash>restart</on_crash>  <devices>    <emulator>/usr/bin/qemu-kvm</emulator>    <disk type='file' device='disk'>      <driver name='qemu' type='qcow2'/>      <source file='/var/run/media/hattori/USB_HDD/libvirt_images/jeos-f16-sda.qcow2'/>      <target dev='vda' bus='virtio'/>      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>    </disk>    <controller type='usb' index='0'>      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>    </controller>    <interface type='network'>      <mac address='52:54:00:ef:e8:f6'/>      <source network='default'/>      <model type='virtio'/>      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>    </interface>    <serial type='pty'>      <target port='0'/>    </serial>    <console type='pty'>      <target type='serial' port='0'/>    </console>    <input type='tablet' bus='usb'/>    <input type='mouse' bus='ps2'/>    <graphics type='vnc' port='-1' autoport='yes'/>    <sound model='ich6'>      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>    </sound>    <video>      <model type='cirrus' vram='9216' heads='1'/>      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>    </video>    <memballoon model='virtio'>      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>    </memballoon>  </devices> </domain>

after

<domain type='kvm'>  <name>f16-1</name>  <uuid>6de2733a-f21f-c04f-baec-2f79f7ff45e2</uuid>  <memory unit='KiB'>262144</memory>  <currentMemory unit='KiB'>262144</currentMemory>  <vcpu current='1'>2</vcpu>  <os>    <type arch='x86_64' machine='pc-0.15'>hvm</type>    <boot dev='hd'/>  </os>  <features>    <acpi/>    <apic/>    <pae/>  </features>  <clock offset='utc'/>  <on_poweroff>destroy</on_poweroff>  <on_reboot>restart</on_reboot>  <on_crash>restart</on_crash>  <devices>    <emulator>/usr/bin/qemu-kvm</emulator>    <disk type='file' device='disk'>      <driver name='qemu' type='qcow2'/>      <source file='/var/run/media/hattori/USB_HDD/libvirt_images/jeos-f16-sda.qcow2'/>      <target dev='vda' bus='virtio'/>      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>    </disk>    <controller type='usb' index='0'>      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>    </controller>    <interface type='direct'>      <mac address='52:54:00:ef:e8:f6'/>      <source dev='p10p1' mode='bridge'/>      <model type='virtio'/>      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>    </interface>    <serial type='pty'>      <target port='0'/>    </serial>    <console type='pty'>      <target type='serial' port='0'/>    </console>    <input type='tablet' bus='usb'/>    <input type='mouse' bus='ps2'/>    <graphics type='vnc' port='-1' autoport='yes'/>    <sound model='ich6'>      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>    </sound>    <video>      <model type='cirrus' vram='9216' heads='1'/>      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>    </video>    <memballoon model='virtio'>      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>    </memballoon>  </devices> </domain>

p10p1 is KVM’s physical NIC name.

[root@fc17 ~]# ls /etc/sysconfig/network-scripts/*p10p1* /etc/sysconfig/network-scripts/ifcfg-p10p1

or you can use macvtap via virt-manager


That’s it ! Your VM’s network interface  will be bridge mode.
There’s no need to associate your KVM host physical interface with bridge interface.

[root@fc17 ~]# ip link show  macvtap0 9: macvtap0@p10p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN mode DEFAULT qlen 500    link/ether 52:54:00:ef:e8:f6 brd ff:ff:ff:ff:ff:f