提示的错误信息：
loaded plugins :fastestmirror ,refresh-packagekit, security
loading mirror speeds from cached hostfile
could not retrieve mirrorlist http://mirrorlist.centos.org/?release=6&arch=i386&repo=os error was 14:pycurl error 6 - "couldn't resolve host 'mirrorlist.centos.org'" error:cannot find a vaild baseurl for repo:base
loading mirror speeds from cached hostfile
could not retrieve mirrorlist http://mirrorlist.centos.org/?release=6&arch=i386&repo=os error was 14:pycurl error 6 - "couldn't resolve host 'mirrorlist.centos.org'" error:cannot find a vaild baseurl for repo:base
没有连接上网络
输入连接网络的命令：ifup eth0 ，回车键提示连接上网络
可以使用yum 在线安装程序了