定义CentOS非官方源，可升级PHP和Mysql到高版本
shell> rpm --import http://www.jasonlitka.com/media/RPM-GPG-KEY-jlitka
shell> vi /etc/yum.repos.d/utterramblings.repo
[utterramblings] name=Jason's Utter Ramblings Repo baseurl=http://www.jasonlitka.com/media/EL$releasever/$basearch/ enabled=1 gpgcheck=1 gpgkey=http://www.jasonlitka.com/media/RPM-GPG-KEY-jlitka
(3) 关闭yum fastestmirror 功能
shell> vi /etc/yum/pluginconf.d/fastestmirror.conf
enabled=0