摘要
修改centos的源
首先备份/etc/yum.repos.d/CentOS-Base.repo
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
进入yum源配置文件所在文件夹
cd /etc/yum.repos.d/
下载163或者阿里云的yum源配置文件，放入/etc/yum.repos.d/(操作前请做好相应备份)
wget http://mirrors.163.com/.help/CentOS6-Base-163.repo # 163
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo # centos5
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo # centos6
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo # centos7
运行yum makecache生成缓存
yum makecache
更新系统
yum -y update