安装Bridge工具软件包
Linux可以工作在网桥模式，必须安装网桥工具bridge-utils，运行命令：
yum install bridge-utils 或 apt-get install bridge-utils
Linux KVM Bridge逻辑结构图
通过命令行创建Bridge
注意：通过命令创建的Brdge在重启后会自动丢失，因此需要在网络配置文件中写入Brdge配置。
# 创建brdge br0
# brctl addbr br0
# 将br0绑定到ens33 # brctl addif br0 ens33
通过网络配置创建创建Bridge
CentOS系统：https://zhidao.baidu.com/question/1046233341920860299.html
Ubuntu Bridge配置示例
auto ens33
iface ens33 inet manual
auto br0 iface br0 inet static address 192.168.1.2 network 192.168.1.0 netmask 255.255.255.0 broadcast 192.168.1.255 bridge_ports eth0 bridge_bridgeprio 32767 bridge_portprio eth0 129 bridge_fd 5
参数
IFACE OPTIONS A little explanation on the new options that can be used on /etc/network/interfaces to setup the bridge, so you don't have to go and look at the scripts... bridge_ports interface specification this option must exist for the scripts to setup the bridge, with it you specify the ports you want to add to your bridge, either using "none" if you want a bridge without any interfaces or you want to add them later using brctl, or a list of the interfaces you want to add separated by spaces, for example: bridge_ports eth0 eth4 You should not put any lines to configure the interfaces that will be used by the bridge, as this will be setup automatically by the scripts when bringing the bridge up. If you need to specify the interfaces more flexibly, you can use the following syntax (most useful on a Xen dom0): bridge_ports regex (eth|vif).* This means to evaluate (as in egrep(1)) the expressions that follow after "regex" until either the end or a "noregex" statement is reached. The regular expressions are evaluated against all local interfaces and those that match are added. Specifying "all" is short for "regex eth.* em.* p[0-9].* noregex" and will get all the ethX and biosdevname-format (emX and pX) interfaces added to the bridge. Carrying this to the extremes, the following is valid syntax: bridge_ports all regex if.0 noregex ext0 regex vif.* This will add all ethX interfaces, the ifX0 interfaces, the ext0 interface and all vifX interfaces. bridge_ageing time set ageing time, default is 300, can have a fractional part. bridge_bridgeprio priority set bridge priority, priority is between 0 and 65535, default is 32768, affects bridge id, lowest priority bridge will be the root. bridge_fd time set bridge forward delay to time seconds, default is 15, can have a fractional part. bridge_gcint time set garbage collection interval to time seconds, default is 4, can have a fractional part. Available on Linux kernel versions < 2.6.0. bridge_hello time set hello time to time seconds, default is 2, can have a fractional part. bridge_hw MAC address set the Ethernet MAC address of the bridge to the specified one. There were some concerns of how this was done in the past, see: http://bugs.debian.org/271406 but we are doing it on a new way now that shouldn't be as bad, see: http://bugs.debian.org/725786 however you should know what you are doing before using this option. bridge_maxage time set max message age to time seconds, default is 20, can have a fractional part. bridge_maxwait time forces to time seconds the maximum time that the Debian bridge setup scripts will wait for the bridge ports to get to the forwarding status, doesn't allow factional part. If it is equal to 0 then no waiting is done. bridge_pathcost port cost set path cost for a port, default is 100, port is the name of the interface to which this setting applies. bridge_portprio port priority set port priority, default is 32, affects port id, port is the name of the interface to which this setting applies. On Linux kernels older than 2.6.0 the max value is 255, the default 128. Newer kernels have a maximum value of 63 and a default of 32. bridge_stp state turn spanning tree protocol on/off, state values are on or yes to turn stp on and any other thing to set it off, default has changed to off for security reasons in latest kernels, so you should specify if you want stp on or off with this option, and not rely on your kernel's default behaviour. bridge_waitport time [ports] wait for a max of time seconds for the specified ports to become available, if no ports are specified then those specified on bridge_ports will be used here. Specifying no ports here should not be used if we are using regex or "all" on bridge_ports, as it wouldn't work.