为CentOS虚拟机添加第二块网卡

为CentOS虚拟机添加第二块网卡

使用virt-install安装了一个CentOS虚拟机，安装过程未指定网络参数，默认使用内置虚拟NAT的方式上网，现在希望给虚拟机另外安装一块虚拟的网卡，然后给其分配一个外网IP地址（与宿主机处于同一网段）。

安装CentOS

$ sudo virt-install --connect qemu:///system --noautoconsole \
-n centos -r 4096 --vcpus=4 --arch=x86_64 --os-type=linux \
--os-variant=rhel6 --accelerate -v -l http://mirrors.163.com/centos/6.3/os/x86_64/ \
--disk path=/var/lib/libvirt/images/centos.img,size=200 \
--graphics vnc,password=foobar,listen=0.0.0.0,port=5901

为宿主机添加虚拟网桥

$ vim /etc/network/interfaces

修改如下

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
iface em1 inet manual

auto br0
iface br0 inet static
bridge_ports    em1
bridge_stp  on
bridge_maxwait  0
bridge_fd   0
address     192.168.18.130
netmask     255.255.255.0
network     192.168.18.0
broadcast   192.168.18.255
gateway     192.168.18.1
dns-nameservers 192.168.18.1

添加虚拟网桥配置br0,并且把主网卡em1（大多数情况下主网卡为eth0）配置由dhcp或者static改成manual。然后重启网络服务

$ sudo service networking restart

为虚拟机添加一张额外的虚拟网卡

首先关闭VM

$ virsh destory centos

然后编辑VM配置文件

$ virsh edit centos

在之后加入如下xml片段

<interface type='bridge'>
<mac address='00:16:3e:1a:b3:4a'/>
<source bridge='br0'/>
<model type='virtio'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
</interface>

然后保存退出。启动刚才修改过的VM虚拟节点

$ virsh start centos

为CentOS添加新网卡配置

参看

/sys/class/net

可以看到新添加的网卡eth1

# ls /sys/class/net/
eth0  eth1  lo

通过ifconfig获得该网卡的MAC地址

# ifconfig eth1
eth1    Link encap:Ethernet  HWaddr 00:16:3E:1A:B3:4A
inet addr:192.168.18.210  Bcast:192.168.18.255  Mask:255.255.255.0
inet6 addr: fe80::216:3eff:fe1a:b34a/64 Scope:Link
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:3343 errors:0 dropped:0 overruns:0 frame:0
TX packets:12 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:216373 (211.3 KiB)  TX bytes:1364 (1.3 KiB)

执行uuidgen生成一个随机的UUID

# uuidgen
e5281311-f265-4afa-a7e1-4d76718f7de0

然后完事具备只欠东方了，

# cd /etc/sysconfig/network-scripts
# cp ifcfg-eth0 ifcfg-eth1
# vim ifcfg-eth1

结合上面的MAC地址和UUID，修改内容如下

DEVICE="eth1"
BOOTPROTO="dhcp"
HWADDR="00:16:3E:1A:B3:4A"
IPV6INIT="yes"
IPV6_AUTOCONF="yes"
NM_CONTROLLED="yes"
ONBOOT="yes"
TYPE="Ethernet"
UUID="e5281311-f265-4afa-a7e1-4d76718f7de0"