继上文《Ubuntu14.04安装配置Open vSwitch》安装好Open vSwitch后，这里我们将要创建两个KVM虚拟机，并通过DNSmasq来为这两个虚拟机自动分配私网IP地址。
虚拟机与宿主机网络结构图大致如下所示：
测试环境说明：
1）测试私网段：172.17.0.0/24
2）测试 vlan tag：100
下面简要介绍下整个配置流程：
1、安装dnsmasq：
◄► sudo apt-get install dnsmasq
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
dnsmasq
upgraded, newly installed, to remove and not upgraded.
Need to get 14.9 kB of archives.
After this operation, kB of additional disk space will be used.
Get: http://cn.archive.ubuntu.com/ubuntu/ trusty-updates/universe dnsmasq all 2.68-1ubuntu0.1 [14.9 kB]
Fetched 14.9 kB in 0s ( kB/s)
Selecting previously unselected package dnsmasq.
(Reading database ... files and directories currently installed.)
Preparing to unpack .../dnsmasq_2.-1ubuntu0.1_all.deb ...
Unpacking dnsmasq (2.68-1ubuntu0.) ...
Processing triggers for ureadahead (0.100.-) ...
ureadahead will be reprofiled on next reboot
Setting up dnsmasq (2.68-1ubuntu0.) ...
* Starting DNS forwarder and DHCP server dnsmasq [ OK ]
Processing triggers for ureadahead (0.100.-) ...
◄► sudo ps -ea | grep dns
? :: dnsmasq
2、通过 ovs 创建一个 internal port，这里取名为 qdhcp，并设置 vlan id 为100，供下文的 dnsmasq 进程使用：
◄► sudo ovs-vsctl add-port br0 qdhcp tag=
◄► sudo ovs-vsctl set Interface qdhcp type=internal
3、查看已经创建的 qdhcp port：
◄► sudo ovs-vsctl show
1e6548a9-956e-4b86-b743-f8da0aa2b922
Bridge "br0"
Port "br0"
Interface "br0"
type: internal
Port qdhcp
tag:
Interface qdhcp
type: internal
Port "eth0"
Interface "eth0"
ovs_version: "2.0.2"
◄► ifconfig qdhcp Link encap:Ethernet HWaddr :6c:a8:c2::
inet6 addr: fe80::706c:a8ff:fec2:/ Scope:Link
UP BROADCAST RUNNING MTU: Metric:
RX packets: errors: dropped: overruns: frame:
TX packets: errors: dropped: overruns: carrier:
collisions: txqueuelen:
RX bytes: (0.0 B) TX bytes: (578.0 B)
4、给 qdhcp 虚拟网卡配置 IP 地址，这里IP地址必须为测试私网内的，这里我们就分配 172.17.0.1 给qdhcp：
◄► sudo ifconfig qdhcp 172.17.0.1 netmask 255.255.255.0 up
◄► ifconfig qdhcp Link encap:Ethernet HWaddr :6c:a8:c2::
inet addr:172.17.0.1 Bcast:172.17.0.255 Mask:255.255.255.0
inet6 addr: fe80::706c:a8ff:fec2:/ Scope:Link
UP BROADCAST RUNNING MTU: Metric:
RX packets: errors: dropped: overruns: frame:
TX packets: errors: dropped: overruns: carrier:
collisions: txqueuelen:
RX bytes: (0.0 B) TX bytes: (648.0 B)
5、启动一个 dnsmasq 进程，监听 qdhcp 虚拟网卡：
◄► sudo /usr/sbin/dnsmasq --strict-order --bind-interfaces --interface=qdhcp --except-interface=lo --pid-file=/var/run/dnsmasq/qdhcp.pid --leasefile-ro --dhcp-range=172.17.0.2,172.17.0.254,255.255.255.0,12h --conf-file=
6、查看已经启动的 dnsmasq 进程：
◄► ps aux | grep dnsmasq
nobody 0.0 0.0 ? S : : /usr/sbin/dnsmasq --strict-order --bind-interfaces --interface=qdhcp --except-interface=lo --pid-file=/var/run/dnsmasq/qdhcp.pid --leasefile-ro --dhcp-range=172.17.0.2,172.17.0.254,255.255.255.0,12h --conf-file=
7、下面就是整理两个虚拟机VM1、VM2的配置文件，这里仅展示 interface 这块配置项：
VM1：
<interface type='bridge'>
<source bridge='br0'/>
<vlan>
<tag id='100'/>
</vlan>
<virtualport type='openvswitch'/>
<target dev='tap0'/>
<model type='virtio'/>
</interface> VM2：
<interface type='bridge'>
<source bridge='br0'/>
<vlan>
<tag id='100'/>
</vlan>
<virtualport type='openvswitch'/>
<target dev='tap0'/>
<model type='virtio'/>
</interface>
这里将两个虚拟机的虚拟网卡的 vlan id 都设为 100，即必须保证和 qdhcp port在同一个vlan中。
8、启动VM1、VM2，并查看 ovs 虚拟网卡 tap0、tap1 的情况：
◄► sudo ovs-vsctl show
1e6548a9-956e-4b86-b743-f8da0aa2b922
Bridge "br0"
Port "tap1"
tag:
Interface "tap1"
Port "br0"
Interface "br0"
type: internal
Port qdhcp
tag:
Interface qdhcp
type: internal
Port "eth0"
Interface "eth0"
Port "tap0"
tag:
Interface "tap0"
ovs_version: "2.0.2"
由此，我们已经将VM1、VM2和qdhcp port分在了同一个VLAN里了。
10、通过VNC登陆到VM1、VM2中，查看其是否获取到指定私网段IP地址：
VM1：
VM2：
11、从VM1 ping VM2：
至此，整合Open vSwitch与DNSmasq的功能就完成了，两个虚拟机之间就可以愉快地玩耍了。