2015-12-15 QEMU Network Setup

QEMU Network Setup

QEMU Network Setting

上周配置QEMU的网络设置用了很大功夫，终于彻底弄明白了。

需求：首先要清楚，因为我要修改QEMU代码，所以不能用virsh来自动配置，因为它采用的是qemu-kvm，进行了特殊的订制，可能会有不必要的麻烦。我需要自己

make install

之后，用

qemu-system-x86_64

来手动启动虚拟机。

结构：在Host中，创建桥接网络virbr0，并且将eth0连入此桥接网络。然后在Guest中，修改

network-scripts

，正确识别并设置QEMU的网卡e1000。最后，编写Host中的QEMU启动脚本，将Guest连入virbr0。

Host Setting

REMEMBER TO CHECK NETWORK CABLE CONNECTION FIRST!!!我浪费了好多时间在配置脚本上，总是无法正确设置网络，结果发现网线松动了。

Enter

/etc/sysconfig/network-scripts/

Add ifcfg-virbr0

Edit ifcfg-eth0(maybe enp3s0,enp2s0),add it to virbr0

service network restart

brctl show  //To ensure correctness

QEMU scripts

Edit runkvm for correct img path

Edit qemu-ifup for correct bridge name

Guest Setting

Run

runkvm

to start guest and enter it with root

cd /etc/udev/rules.d/

cat 70-persistent-net.rules

PCI device e1000 is QEMU network adapter,remember its NAME(eth0/1/2) and ATTR

Add eth0/1/2 scripts under network-scripts:

cd /etc/sysconfig/network-scripts/

cp ifcfg-eth0 ifcfg-eth1(If qemu network adapter is eth0,normal setting should work,and we don't need to edit,just ifconfig to check network connection.)

vim ifcfg-eth1

Change HWADDR to ATTR in

70-persistent-net.rules

service network restart

Explanation: 因为之前都是在做Xen的虚拟化，所以这个镜像中配置的

network-scripts

是指定的Xen的网卡作为eth0，现在采用QEMU了，缺少对应的网络配置脚本，那么直接在

network-scripts

中加入新的脚本配置QEMU网卡就可以了。

Setting files

ifcfg-virbr0

TYPE=Bridge
STP=yes
BOOTPROTO=none
NAME=virbr0
UUID=cc49c39a-8713-4c88-b877-557a462ab738
DEVICE=virbr0
ONBOOT=yes
DNS1=162.105.129.26
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=no
DELAY=0
BRIDGINS_OPTS=priority=32768
IPADDR=172.17.2.131
PREFIX=16
GATEWAY=172.17.1.1
NM_CONTROLLED=no

ifcfg-enp3s0

BRIDGE=virbr0
BOOTPROTO=none
NAME=enp3s0
UUID=cc49c39a-8713-4c88-b877-557a462ab738
DEVICE=enp3s0
ONBOOT=yes
NM_CONTROLLED=no

runkvm

#!/bin/bash

qemu-system-x86_64 -enable-kvm -nographic -m 8192 -smp 3,sockets=3,cores=1,threads=1 -device e1000,netdev=net0 -netdev tap,id=net0,script=./qemu-ifup -device virtio-balloon-pci,id=balloon0,bus=pci.0 /root/richard/test/centos6.img

qemu-ifup

#!/bin/sh
set -x

switch=virbr0

if [ -n "$1" ];then
echo "qemu-ifup argument: interface "$1
#/usr/bin/sudo /usr/sbin/tunctl -u `whoami` -t $1
/usr/bin/sudo /sbin/ip link set $1 up
sleep 0.5s
/usr/bin/sudo /usr/sbin/brctl addif $switch $1
exit 0
else
echo "Error: no interface specified"
exit 1
fi