1.下載repo文件
cd /etc/yum.repos.d/ && cp CentOS-Base.repo CentOS-Base.repo.bak
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
2.更改發行版本及CPU體系架構參數值(basearch)
sed 's#/$releasever#/6#g;s#/$basearch#/x86_64#g' CentOS-Base.repo
3.清空並新生成yum緩存
yum clean all
yum makecache
yum update(服務器謹慎更新)