O0十一、理解 virbr0

參考 http://www.javashuo.com/article/p-yipctwae-hk.html

 

virbr0 是KVM 默認建立的一個Bridge ，其做用是爲該宿主機上的虛機提供NAT上網的功能。virbr0默認分配了一個IP地址 192.168.122.1 併爲鏈接在上面的虛擬網卡提供DHCP服務。

 

下面咱們演示如何使用 virbr0

 

建立虛機 VM3 ，並設置網卡鏈接到 NAT 網絡中

 

 

root@ubuntu:~# virsh list     #    查看VM3運行狀態

Id    Name                           State

----------------------------------------------------

10    VM3                            running

 

root@ubuntu:~# virsh domiflist VM3    #    查看VM3 虛機接口

Interface  Type       Source     Model       MAC

-------------------------------------------------------

vnet0      network    default    rtl8139     52:54:00:e3:0f:d2

 

root@ubuntu:~# brctl show    #    查看 VM3 虛機接口鏈接到了 virbr0 上

bridge name    bridge id        STP enabled    interfaces

br0        8000.005056874c70    no        ens160

virbr0        8000.fe5400e30fd2    yes        vnet0

 

root@ubuntu:~# ps -ef | grep dnsmasq    #    virbr0 使用 dnsmasq提供 DHCP服務

libvirt+  3803     1  0 21:58 ?        00:00:00 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper

root      3804  3803  0 21:58 ?        00:00:00 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper

root      6121  5694  0 23:03 pts/3    00:00:00 grep --color=auto dnsmasq

 

root@ubuntu:~# cat /var/lib/libvirt/dnsmasq/default.conf    #    DHCP 配置文件

##WARNING:  THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE

##OVERWRITTEN AND LOST.  Changes to this configuration should be made using:

##    virsh net-edit default

## or other application using the libvirt API.

##

## dnsmasq conf file created by libvirt

strict-order

user=libvirt-dnsmasq

pid-file=/var/run/libvirt/network/default.pid

except-interface=lo

bind-dynamic

interface=virbr0

dhcp-range=192.168.122.2,192.168.122.254

dhcp-no-override

dhcp-lease-max=253

dhcp-hostsfile=/var/lib/libvirt/dnsmasq/default.hostsfile

addn-hosts=/var/lib/libvirt/dnsmasq/default.addnhosts

 

 

在虛機中進行網絡連通性測試，DHCP或得的IP地址能夠ping同宿主機和宿主機外面的網絡