O010、动手实践虚拟网络
本节将演示如何在实验环境中实现下图所示的虚拟网络
配置Linux Bridge br0
编辑 /etc/network/interfaces ,配置br0
root@ubuntu:~# cat /etc/network/interfaces # 修改前，网络信息配置在ens160下
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
source /etc/network/interfaces.d/*
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto ens160
iface ens160 inet static
address 10.12.31.211
netmask 255.255.252.0
network 10.12.28.0
broadcast 10.12.31.255
gateway 10.12.28.6
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 10.12.28.6
up route add -net 172.22.0.0 netmask 255.255.0.0 gw 10.12.28.1 ens160
root@ubuntu:~# cat /etc/network/interfaces # 修改后，ens160挂载br0下，网络信息配置在br0上
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
source /etc/network/interfaces.d/*
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto ens160
iface ens160 inet static
auto br0
iface br0 inet static
bridge_stp off
bridge_waitport 0
bridge_fd 0
bridge_ports ens160
address 10.12.31.211
netmask 255.255.252.0
network 10.12.28.0
broadcast 10.12.31.255
gateway 10.12.28.6
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 10.12.28.6
up route add -net 172.22.0.0 netmask 255.255.0.0 gw 10.12.28.1 br0
root@ubuntu:~# reboot # 重启系统生效
root@ubuntu:~# ifconfig # 查看网络信息都配置到了br0上
br0 Link encap:Ethernet HWaddr 00:50:56:87:4c:70
inet addr:10.12.31.211 Bcast:10.12.31.255 Mask:255.255.252.0
inet6 addr: fe80::250:56ff:fe87:4c70/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:307 errors:0 dropped:0 overruns:0 frame:0
TX packets:129 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:19800 (19.8 KB) TX bytes:18385 (18.3 KB)
ens160 Link encap:Ethernet HWaddr 00:50:56:87:4c:70
inet6 addr: fe80::250:56ff:fe87:4c70/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:314 errors:0 dropped:0 overruns:0 frame:0
TX packets:160 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:24520 (24.5 KB) TX bytes:22247 (22.2 KB)
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:65536 Metric:1
RX packets:85 errors:0 dropped:0 overruns:0 frame:0
TX packets:85 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:6165 (6.1 KB) TX bytes:6165 (6.1 KB)
virbr0 Link encap:Ethernet HWaddr 00:00:00:00:00:00
inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
root@ubuntu:~# brctl show # 查看 ens160 挂到了br0 下
bridge name bridge id STP enabled interfaces
br0 8000.005056874c70 no ens160
virbr0 8000.000000000000 yes
除了br0 ，我们还能看到一个 virbr0 的Bridge ，而且 virbr0 上已经配置了IP 地址 192.168.122.1 。virbr0 的作用我们后面会介绍。
创建虚机VM1 和 VM2
root@ubuntu:~# virsh list # 查看虚拟列表
Id Name State
----------------------------------------------------
6 VM1 running
7 VM2 running
设置KVM虚机 vnc 端口、密码、监听地址的方法
<graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0' passwd='qB6wbeu39BXnH8JxGTltbeQoLvGjvwax'>
<listen type='address' address='0.0.0.0'/>
</graphics>
配置VM1 和 VM2
将VM1的虚拟网卡连接到br0上，VM2也做同样操作
root@ubuntu:~# virsh domiflist VM1 # 查看VM1网卡信息
Interface Type Source Model MAC
-------------------------------------------------------
vnet0 bridge br0 rtl8139 52:54:00:58:af:ef
在VM1 中给eth0 配置 IP 地址 10.12.31.241/22 ，测试网络连通性
在VM2 中给eth0 配置 IP 地址 10.12.31.242/22 ，测试网络连通性
以上实验证明了 VM1、VM2、宿主机以及宿主机以外的网络是可以互相通信的。
ps：因为这里是在esxi 上部署的kvm，所以该kvm连接的esxi网络需要接受混杂模式
