第一步：rpm -qa |grep yum |xargs rpm -e --nodeps第二步：root@agent:/root#rpm -qa |grep  python-urlgrabberpython-urlgrabber-3.9.1-9.el6.noarchroot@agent:/root#rpm -e  python-urlgrabber第三步：下载如下rpm包        python-urlgrabber-3.9.1-11.el6.noarch.rpm 	yum-3.2.29-73.el6.centos.noarch.rpm        yum-metadata-parser-1.1.2-16.el6.x86_64.rpm         yum-plugin-fastestmirror-1.1.30-37.el6.noarch.rpm第五步：安装rpm -ivh *.rpm第六步：修改sed -i 's/\$releasever/6/g' /etc/yum.repos.d/CentOS-Base.repo第七步：缓存yum clean allyum  makecache