Ubuntu系统重启后/etc/resolv.conf内容丢失

简介

简要介绍如何解决Ubuntu系统重启后/etc/resolv.conf内容丢失问题，或者说解决永久保存/etc/resolv.conf配置问题。

方案1 通过/etc/network/interfaces配置

通过向/etc/network/interfaces接口配置文件追加dns-nameserver和dns-search项来永久保存配置，保存完成后执行"sudo service networing restart"重启网络来触发更新/etc/resolv.conf文件。

The ifup program can be used to configure network interfaces according to settings in /etc/network/interfaces. To  make
ifup  push  nameserver  information  to resolvconf when it configures an interface the administrator must add dns- option
lines to the relevant  iface  stanza  in  interfaces(5).   The  following  option  names  are  accepted:  dns-nameserver,
dns-search, and dns-sortlist.

To  add  a nameserver IP address, add an option line consisting of dns-nameserver and the address.  To add multiple name
server addresses, include multiple such dns-nameserver lines.

dns-nameserver 192.168.1.254
dns-nameserver 8.8.8.8

To add search domain names, add a line beginning with dns-search.

dns-search foo.org bar.com

The dns-nameservers option is also accepted and, unlike dns-nameserver, can be given  multiple  arguments,  separated  by
spaces.

The dns-domain option is deprecated in favor of dns-search.

The resulting stanza might look like the following example.

iface eth0 inet static
address 192.168.1.3
netmask 255.255.255.0
gateway 192.168.1.1
dns-nameserver 192.168.1.254
dns-nameserver 8.8.8.8
dns-search foo.org bar.com

方案2 通过resolvconf实现配置

resolvconfig应用可以实现DNS信息管理，可以通过下面的应用来安装此组件：

sudo apt-get install resolvconf

创建/etc/default/resolvconf缺省配置文件，添加相关环境变量

bob@ubuntu:/etc/resolvconf/resolv.conf.d$ cat /etc/default/resolvconf
TRUNCATE_NAMESERVER_LIST_AFTER_127=no

该环境变量影响保存到/etc/resolv.conf的DNS配置条数。向/etc/resolvconf/resolv.conf/base配置文件中添加DNS配置项。

bob@ubuntu:/etc/resolvconf/resolv.conf.d$ cat base
nameserver 10.220.0.11
nameserver 10.220.0.12
search infinera.com

使用下列配置命令使配置生效

sudo resolvconf -u

总结

以上两种配置方式均可实现/etc/resolv.conf配置永久保存功能，更具体的信息可以查看"man resolvconf"手册。