KVM的默认网络模式为NAT，就是说借助宿主机模式上网，现在我们想改成桥接模式，，这样外界就可以直接和宿主机里的虚拟机通讯了。1，首先看一下默认的网络设置# cat /etc/libvirt/qemu/networks/default.xml <network> <name>default</name> <uuid>1f118032-0345-4725-adcf-6b94f6aca19c</uuid> <bridge /> <mac address=’52:54:00:F1:6B:6E’/> <forward/> <ip address=”192.168.122.1″ netmask=”255.255.255.0″> <dhcp> <range start=”192.168.122.2″ end=”192.168.122.254″ /> </dhcp> </ip></network>2，再看一下虚拟机配置文件里面的网络设置#cat /etc/libvirt/qemu/Ubuntu10.04.xml<!–WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE OVERWRITTEN AND LOST. Changes to this xml configuration should be made using: virsh edit ubuntu10.04or other application using the libvirt API.–><domain type=’kvm’> <name>ubuntu10.04</name> <uuid>2eeb1395-39a2-a169-4da3-f22b20a1d34f</uuid> <memory unit=’KiB’>1048576</memory> <currentMemory unit=’KiB’>1048576</currentMemory> <vcpu placement=’static’>1</vcpu> <os> <type arch=’x86_64′ machine=’rhel6.3.0′>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/libexec/qemu-kvm</emulator> <disk type=’file’ device=’disk’> <driver type=’raw’ cache=’none’/> <source file=’/var/lib/libvirt/images/ubuntu10.04.img’/> <target dev=’vda’ bus=’virtio’/> <address type=’pci’ domain=’0x0000′ bus=’0x00′ slot=’0x05′ function=’0x0’/> </disk> <disk type=’block’ device=’cdrom’> <driver type=’raw’/> <target dev=’hdc’ bus=’ide’/> <readonly/> <address type=’drive’ controller=’0′ bus=’1′ target=’0′ unit=’0’/> </disk> <controller type=’usb’ index=’0′> <address type=’pci’ domain=’0x0000′ bus=’0x00′ slot=’0x01′ function=’0x2’/> </controller> <controller type=’ide’ index=’0′> <address type=’pci’ domain=’0x0000′ bus=’0x00′ slot=’0x01′ function=’0x1’/> </controller> <interface type=’bridge’> 原来是interface type=’default’ <mac address=’52:54:00:50:58:7e’/> <source bridge=’br1’/> 原来是source network=’default’,这里的br1要根据你的物理网卡下面有讲 <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=’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>3，改完之后要更新一下配置文件# virsh define ubuntu10.04.xml定义域 ubuntu10.04（从 ubuntu10.04.xml）#然后就可以virsh start ubuntu10.04了，不过现在物理网卡这块还没有改好
天下无难事，只怕有心人。
