linux安装软件时提示找不到镜像的问题：Couldn't resolve host 'mirrorlist.centos.org'

[root@sulei sulei]# yum install docker
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=os error was
14: PYCURL ERROR 6 - “Couldn’t resolve host ‘mirrorlist.centos.org’”
Error: Cannot find a valid baseurl for repo: base
解决办法：
没有配置：
dns服务器没有配置正确

1、打开文件/etc/resolv.conf在其中添加：
 nameserver 8.8.8.8
 nameserver 8.8.4.4
 search localdomain

2、然后重启网卡：使用命令: service network restart