更改yum源为网易的。
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
cd /etc/yum.repos.d/
yum install wget -y
wget http://mirrors.163.com/.help/CentOS6-Base-163.repoyum clean all
yum makecache