网易官方源
centos7.x
cd /etc/yum.repos.d/
mv CentOS-Base.repo CentOS-Base.repo.$(date +%F)
wget http://mirrors.163.com/.help/CentOS7-Base-163.repo
yum clean all
yum makecache
RHEL 官方扩展源
yum -y install http://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
阿里官方yum源
CentOS 6.x
cd /etc/yum.repos.d/
mv CentOS-Base.repo CentOS-Base.repo.$(date +%F)
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
yum clean all
yum makecache
阿里官方yum源
CentOS 7.x
cd /etc/yum.repos.d/
mv CentOS-Base.repo CentOS-Base.repo.$(date +%F)
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
yum clean all
yum makecache
原文：http://blog.51cto.com/13707680/2104644