1.利用resolvconf：
安装resolvconf：
apt-get install resolvconf
修改 /etc/resolvconf/resolv.conf.d/base
nameserver 8.8.8.8
重启虚拟机，dns将被自动写入 /etc/resolv.conf
2.修改interfaces：
修改 /etc/network/interfaces，例如：
auto eth0
iface eth0 inet static
address 112.23.11.18
netmask 255.255.255.128
gateway 112.213.110.29
auto eth1
iface eth1 inet static
address 10.0.151.34
netmask 255.0.0.0
dns-nameservers 8.8.8.8 114.114.114.114 223.5.5.5
重启虚拟机，配置生效到 /etc/resolv.conf中。