CentOS官方发布了CR升级库，这表明CentOS 6.1的发布可能又要延期了。
安装yum配置文件：yum install centos-release-cr，官方的镜像不大稳定，建议使用mirrors.163.com。
# CentOS-CR.repo
#
# The continuous release ( CR ) repository contains rpms from the
# next point release of CentOS, which isnt itself released as yet.
#
# Look at http://wiki.centos.org/AdditionalResources/Repositories/CR
# for more details about how this repository works and what users
# should expect to see included / excluded
[cr]
name=CentOS-$releasever - CR
baseurl=http://mirrors.163.com/centos/$releasever/cr/$basearch/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
yum update 就发现很多更新可以下载。