1、环境准备
1.1、桥接命令查看
1.1.1、安装桥操作工具
安装桥操作工具：bridge-utils
apt install bridge-utils -y
apt-file list bridge-utils
1.1.2、命令查看
# brctl --help
Usage: brctl [commands]
commands:
addbr <bridge> add bridge
delbr <bridge> delete bridge
addif <bridge> <device> add interface to bridge
delif <bridge> <device> delete interface from bridge
hairpin <bridge> <port> {on|off} turn hairpin on/off
setageing <bridge> <time> set ageing time
setbridgeprio <bridge> <prio> set bridge priority
setfd <bridge> <time> set bridge forward delay
sethello <bridge> <time> set hello time
setmaxage <bridge> <time> set max message age
setpathcost <bridge> <port> <cost> set path cost
setportprio <bridge> <port> <prio> set port priority
show [ <bridge> ] show a list of bridges
showmacs <bridge> show a list of mac addrs
showstp <bridge> show bridge stp info
stp <bridge> {on|off} turn stp on/off
1.2、查看宿主IP地址
# ip addr
...
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:95:33:c8 brd ff:ff:ff:ff:ff:ff
altname enp2s1
inet 192.168.10.21/24 brd 192.168.10.255 scope global ens33
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fe95:33c8/64 scope link
valid_lft forever preferred_lft forever
3: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 52:54:00:eb:07:52 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
valid_lft forever preferred_lft forever
4: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master virbr0 state UNKNOWN group default qlen 1000
link/ether fe:54:00:f4:2d:fc brd ff:ff:ff:ff:ff:ff
inet6 fe80::fc54:ff:fef4:2dfc/64 scope link
valid_lft forever preferred_lft forever
1.3、查看路由
# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.10.2 0.0.0.0 UG 0 0 0 ens33
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 ens33
192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0
1.4、配置DNS解析地址
# vi /etc/resolv.conf
nameserver 192.168.10.2
options edns0 trust-ad
search .
2、桥接设备
2.1、手动创建
2.1.1、创建桥接网卡设备
brctl addbr br0
brctl stp br0 on
2.1.2、删除物理网卡的ip地址
ifconfig ens33 0 up
# 注意:此时ssh无法链接了,建议使用脚本操作
2.1.3、关联桥接设备和物理网卡设备
2.1.4、给桥接网卡配置ip地址并启动
ifconfig br0 192.168.10.200/24 up
2.1.5、给桥接网卡配置路由
route add default gw 192.168.10.2
# 注意： 操作br0的另一种方法是 ip set dev br0 up/down
2.1.6、检查效果
root@localhost:~# ifconfig
br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.10.200 netmask 255.255.255.0 broadcast 192.168.10.255 # 此时，物理机的IP地址，已经换成192.168.10.200了
inet6 fe80::7048:e6ff:feff:a96a prefixlen 64 scopeid 0x20<link>
ether 72:48:e6:ff:a9:6a txqueuelen 1000 (Ethernet)
RX packets 43 bytes 5210 (5.2 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 38 bytes 6907 (6.9 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 # 无IP地址了
inet6 fe80::20c:29ff:fe95:33c8 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:95:33:c8 txqueuelen 1000 (Ethernet)
RX packets 12859 bytes 1147776 (1.1 MB)
RX errors 0 dropped 2 overruns 0 frame 0
TX packets 37144 bytes 48296917 (48.2 MB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
...
2.2、脚本创建
#如果将命令分开执行的话，则会在关联桥接网卡和物理网卡的时候造成断网现象，所以建议将这几条命令同时 执行或者使用脚本执行命令
cat << 'CAT_NED' > add_br0.sh
#!/bin/bash
brctl addbr br0
brctl stp br0 on
ifconfig ens33 0 up
brctl addif br0 ens33
ifconfig br0 192.168.10.21/24 up
route add default gw 192.168.10.2
CAT_NED
3、虚拟机网络配置
3.1、修改虚拟机的网卡配置
# virsh edit CentOS-8-x86_64
...
<interface type='bridge'>
<mac address='52:54:00:f4:2d:fc'/>
<source bridge='br0'/>
<model type='virtio'/>
<address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
</interface>
...
修改了三处地方：
type后面的network修改为了bridge
source后面的network修改为了bridge,network后面的default修改为了br0
3.2、重启虚拟机
virsh shutdown CentOS-8-x86_64
virsh start CentOS-8-x86_64
3.3、查看获取的IP地址
# ip addr2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 52:54:00:f4:2d:fc brd ff:ff:ff:ff:ff:ff
inet 192.168.10.22/24 brd 192.168.10.255 scope global noprefixroute dynamic eth0 # 是跟宿主机一样的网段
...
3.4、宿主机测试
root@localhost:~# ssh root@192.168.10.22 ip addr
root@192.168.10.22's password:
...
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 52:54:00:f4:2d:fc brd ff:ff:ff:ff:ff:ff
inet 192.168.10.22/24 brd 192.168.10.255 scope global noprefixroute dynamic eth0
...
3.5、将虚拟机IP地址修改为固定
3.5.1、修改配置
]# vi /etc/sysconfig/network-scripts/ifcfg-eth0
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=eth0
UUID=fe3b0f99-eef3-49b3-b54f-3b06c0b78f65
DEVICE=eth0
ONBOOT=yes
IPADDR=192.168.10.22
PREFIX=24
GATEWAY=192.168.10.2
DNS1=8.8.8.8
3.5.2、重启网络 或者 重启虚拟机
注意：centos8环境下重启网络的命令有些繁琐，不能使用 systemctl restart network
nmcli c reload
nmcli c up eth0
nmcli d reapply eth0
nmcli d connect eth0
