物理主机上有5台kvm虚拟机，需要通过网桥的方式使其与外界通信。为了达到这个目的，需要将5台虚拟机的虚拟网卡（vnet0-vnet4）以及物理主机对外通信的物理网卡（这里为eth0）连接到同一个网桥（br0）上。物理主机操作系统为rhel6.3，虚拟机操作系统为rhel5.6。下面将记录如何通过创建网桥的方式来使kvm虚拟机与外界通信。
注意：
以下的操作可能导致网络中断，请在物理主机操作。
vhost NIC Bridge Phy NIC
|vnet0|
|vnet1|
|vnet2|———–>|br0|——->| eth0 |——>LAN
|vnet3|
|vnet4|
通过命令行方式来创建网桥
1.检查是否安装了相关的包
rpm -qa | grep bridge-utils
如果未安装，可以使用yum或者直接rpm的方式进行安装。
yum install bridge-utils
关闭NetworkManager服务
/etc/init.d/NetworkManager stop
chkconfig –level 35 NetworkManager off
检查网络配置
[root@node2 ~]# ifconfig
eth0 Link encap:Ethernet HWaddr D4:8C:B5:BC:04:68
inet addr:192.168.10.51 Bcast:10.190.105.255 Mask:255.255.255.0
inet6 addr: fe80::d68c:b5ff:febc:468/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2719 errors:0 dropped:0 overruns:0 frame:0
TX packets:200 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:434192 (424.0 KiB) TX bytes:24782 (24.2 KiB)
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:79957 errors:0 dropped:0 overruns:0 frame:0
TX packets:79957 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:104719505 (99.8 MiB) TX bytes:104719505 (99.8 MiB)
virbr0 Link encap:Ethernet HWaddr 52:54:00:A4:20:F0
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:3389 errors:0 dropped:0 overruns:0 frame:0
TX packets:13814 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:370195 (361.5 KiB) TX bytes:875398 (854.8 KiB)
vnet0 Link encap:Ethernet HWaddr FE:54:00:F1:41:92
inet6 addr: fe80::fc54:ff:fef1:4192/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:210 errors:0 dropped:0 overruns:0 frame:0
TX packets:4581 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:10757 (10.5 KiB) TX bytes:566977 (553.6 KiB)
vnet1 Link encap:Ethernet HWaddr FE:54:00:42:CC:18
inet6 addr: fe80::fc54:ff:fe42:cc18/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:84 errors:0 dropped:0 overruns:0 frame:0
TX packets:4676 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:5564 (5.4 KiB) TX bytes:572720 (559.2 KiB)
vnet2 Link encap:Ethernet HWaddr FE:54:00:5D:EB:0C
inet6 addr: fe80::fc54:ff:fe5d:eb0c/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:209 errors:0 dropped:0 overruns:0 frame:0
TX packets:4562 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:10711 (10.4 KiB) TX bytes:566179 (552.9 KiB)
vnet3 Link encap:Ethernet HWaddr FE:54:00:9F:08:C5
inet6 addr: fe80::fc54:ff:fe9f:8c5/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:211 errors:0 dropped:0 overruns:0 frame:0
TX packets:4545 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:10841 (10.5 KiB) TX bytes:565419 (552.1 KiB)
vnet4 Link encap:Ethernet HWaddr FE:54:00:E7:47:45
inet6 addr: fe80::fc54:ff:fee7:4745/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:211 errors:0 dropped:0 overruns:0 frame:0
TX packets:4549 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:10841 (10.5 KiB) TX bytes:565587 (552.3 KiB)
[root@node2 ~]#
检查虚拟机
[root@node2 ~]# virsh list
Id Name State
—————————————————-
10 node1 running
11 node2 running
12 node3 running
13 node4 running
14 node5 running
2.创建名称为br0的网桥
brctl addbr br0
为br0创建配置文件，使其永久生效
vi /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE=br0
ONBOOT=yes
TYPE=Bridge
BOOTPROTO=none
IPADDR=10.190.105.10
NETMASK=255.255.255.0
STP=on
DELAY=0
使用命令行方式把虚拟网卡(vnet0-vnet4)和物理网卡(eth0)加入到br0
brctl addif br0 vnet0
brctl addif br0 vnet1
brctl addif br0 vnet2
brctl addif br0 vnet3
brctl addif br0 vnet4
brctl addif br0 eth0
[root@node2 ~]# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.d48cb5bc0468 yes eth0
vnet0
vnet1
vnet2
vnet3
vnet4
virbr0 8000.525400a420f0 yes virbr0-nic
[root@node2 ~]#
编辑eth0网卡配置文件，为eth0指定网桥
vi /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
HWADDR=90:b1:1c:11:58:d1
ONBOOT=yes
BRIDGE=br0
重启网络服务
/etc/init.d/network restart
[root@node2 ~]# ifconfig
br0 Link encap:Ethernet HWaddr D4:8C:B5:BC:04:68
inet addr:192.168.10.51 Bcast:10.190.105.255 Mask:255.255.255.0
inet6 addr: fe80::d68c:b5ff:febc:468/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3032 errors:0 dropped:0 overruns:0 frame:0
TX packets:259 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:484624 (473.2 KiB) TX bytes:35056 (34.2 KiB)
eth0 Link encap:Ethernet HWaddr D4:8C:B5:BC:04:68
inet6 addr: fe80::d68c:b5ff:febc:468/64 Scope:Link
UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1
RX packets:562 errors:0 dropped:0 overruns:0 frame:0
TX packets:511 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:97253 (94.9 KiB) TX bytes:75599 (73.8 KiB)
Interrupt:40 Memory:90000000-90012800
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:79969 errors:0 dropped:0 overruns:0 frame:0
TX packets:79969 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:104720105 (99.8 MiB) TX bytes:104720105 (99.8 MiB)
virbr0 Link encap:Ethernet HWaddr 52:54:00:A4:20:F0
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:3389 errors:0 dropped:0 overruns:0 frame:0
TX packets:13817 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:370195 (361.5 KiB) TX bytes:875536 (855.0 KiB)
vnet0 Link encap:Ethernet HWaddr FE:54:00:F1:41:92
inet6 addr: fe80::fc54:ff:fef1:4192/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:215 errors:0 dropped:0 overruns:0 frame:0
TX packets:5011 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:10987 (10.7 KiB) TX bytes:625973 (611.3 KiB)
vnet1 Link encap:Ethernet HWaddr FE:54:00:42:CC:18
inet6 addr: fe80::fc54:ff:fe42:cc18/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:89 errors:0 dropped:0 overruns:0 frame:0
TX packets:5106 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:5794 (5.6 KiB) TX bytes:631716 (616.9 KiB)
vnet2 Link encap:Ethernet HWaddr FE:54:00:5D:EB:0C
inet6 addr: fe80::fc54:ff:fe5d:eb0c/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:214 errors:0 dropped:0 overruns:0 frame:0
TX packets:4992 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:10941 (10.6 KiB) TX bytes:625175 (610.5 KiB)
vnet3 Link encap:Ethernet HWaddr FE:54:00:9F:08:C5
inet6 addr: fe80::fc54:ff:fe9f:8c5/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:216 errors:0 dropped:0 overruns:0 frame:0
TX packets:4975 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:11071 (10.8 KiB) TX bytes:624415 (609.7 KiB)
vnet4 Link encap:Ethernet HWaddr FE:54:00:E7:47:45
inet6 addr: fe80::fc54:ff:fee7:4745/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:216 errors:0 dropped:0 overruns:0 frame:0
TX packets:4979 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:11071 (10.8 KiB) TX bytes:624583 (609.9 KiB)
测试
[root@node2 ~]# ping 192.168.10.1
PING 192.168.10.1 (192.168.10.1) 56(84) bytes of data.
64 bytes from 192.168.10.1: icmp_seq=1 ttl=128 time=0.237 ms
64 bytes from 192.168.10.1: icmp_seq=2 ttl=128 time=0.259 ms
^C
— 192.168.10.1 ping statistics —
2 packets transmitted, 2 received, 0% packet loss, time 1351ms
rtt min/avg/max/mdev = 0.237/0.248/0.259/0.011 ms