CentOS6.3 KVM下设置网卡为桥接模式

CentOS6.3 KVM下设置网卡为桥接模式

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 name="virbr0" />
  <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 ubuntu10.04
or 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 name='qemu' 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 name='qemu' 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


4，物理网卡可以手动更改，不过现在有现成的工具包，可以用这个更改
#wget  http://www.convirture.com/downloads/convirture-tools/2.0.1/convirture-tools-2.0.1.tar.gz
# tar zxvf convirture-tools-2.0.1.tar.gz

# /root/convirture-tools/install/managed_server/scripts/convirt-tool --bridge setup

我的这里出现了点小问题，发现网络没起来，所以不要远程来做这个操作，主要原因是里面的配置文件有点需要
小的更改，我的是UUID注释了。
# ls ifcfg-*
ifcfg-br1  ifcfg-br2  ifcfg-br3  ifcfg-br4  ifcfg-em1  ifcfg-em2  ifcfg-em3  ifcfg-em4  ifcfg-lo
我这里有四个物理网卡，所以生成了四个bridge,不过真实用的只有br1
这个工具好有一个好处就是保存了原配置文件，如果你不想用时还可以还原
# ls saved.ifcfg-em*
saved.ifcfg-em1.20121128.101114  saved.ifcfg-em3.20121128.101114
saved.ifcfg-em2.20121128.101114  saved.ifcfg-em4.20121128.101114
看下ifceg-em1
# cat ifcfg-em1
DEVICE="em1"
#BOOTPROTO=none
NM_CONTROLLED="yes"
ONBOOT=yes
TYPE="Ethernet"
#UUID="3bc7fdcc-42b1-4223-b202-e697305897c8"
#IPADDR172.16.10.81
PREFIX=24
GATEWAY=172.16.10.254
DNS1=172.16.10.5
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="System em1"
HWADDR=90:B1:1C:20:4D:A5
BRIDGE=br1
看下ifcfg-br1
# cat ifcfg-br1
DEVICE="br1"
BOOTPROTO=none
NM_CONTROLLED="yes"
ONBOOT=yes
#UUID="3bc7fdcc-42b1-4223-b202-e697305897c8"
IPADDR=172.16.10.81
PREFIX=24
GATEWAY=172.16.10.254
DNS1=172.16.10.5
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="System br1"
TYPE=Bridge
最后看下网卡
# ifconfig
br1       Link encap:Ethernet  HWaddr 90:B1:1C:20:4D:A5 
          inet addr:172.16.10.81  Bcast:172.16.10.255  Mask:255.255.255.0
          inet6 addr: fe80::92b1:1cff:fe20:4da5/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:10219 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3776 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:576031 (562.5 KiB)  TX bytes:15928008 (15.1 MiB)

em1       Link encap:Ethernet  HWaddr 90:B1:1C:20:4D:A5 
          inet6 addr: fe80::92b1:1cff:fe20:4da5/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:10362 errors:0 dropped:0 overruns:0 frame:0
          TX packets:13131 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:766684 (748.7 KiB)  TX bytes:16489098 (15.7 MiB)
          Interrupt:35

lo        Link encap:Local Loopback 
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:144411 errors:0 dropped:0 overruns:0 frame:0
          TX packets:144411 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:147381248 (140.5 MiB)  TX bytes:147381248 (140.5 MiB)

virbr0    Link encap:Ethernet  HWaddr 52:54:00:F1:6B:6E 
          inet addr:192.168.122.1  Bcast:192.168.122.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2028 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1135 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:233311 (227.8 KiB)  TX bytes:89372 (87.2 KiB)

vnet0     Link encap:Ethernet  HWaddr FE:54:00:50:58:7E 
          inet6 addr: fe80::fc54:ff:fe50:587e/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:161 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3117 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500
          RX bytes:15533 (15.1 KiB)  TX bytes:263947 (257.7 KiB)

vnet1     Link encap:Ethernet  HWaddr FE:54:00:B5:1A:19 
          inet6 addr: fe80::fc54:ff:feb5:1a19/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:56 errors:0 dropped:0 overruns:0 frame:0
          TX packets:794 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500
          RX bytes:8754 (8.5 KiB)  TX bytes:42245 (41.2 KiB)

5,启动虚拟机ubuntu10.04后配置网卡
#cat /etc/network/interface
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
address 172.16.10.100
netmask 255.255.255.0
gateway 172.16.10.254
#/etc/init.d/networking restart
启动即可