配置yum源
确保有wget命令 yum install wget -y
安装阿里云和epel镜像
epel.repo centos-base.repo 指定了yum仓库的网站地址
1.备份现有repo仓库
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
2.下载新的repo文件
CentOS 6
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
CentOS 7
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
3.清空旧yum缓存，生成新的缓存
yum clean all
yum makecache
4.针对阿里云镜像，可能出现无法解析地址的异常
sed -i -e '/mirrors.cloud.aliyuncs.com/d' -e '/mirrors.aliyuncs.com/d' /etc/yum.repos.d/CentOS-Base.repo
5.配置epel源
epel(RHEL 7)
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
epel(RHEL 6)
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-6.repo
epel(RHEL 5)
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-5.repo
再使用 yum clean all 和 yum makecache 来清除缓存和新建缓存
