Page：https://developer.aliyun.com/mirror/

使用说明
CentOS旧版本镜像地址为：https://mirrors.aliyun.com/centos-vault/

• 备份配置文件：
  mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
• 下载新的CentOS-Base.repo 到/etc/yum.repos.d/
  CentOS6：wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
  CentOS7：wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

Page：https://mirrors.huaweicloud.com/

使用说明
CentOS旧版本镜像地址为：https://repo.huaweicloud.com/centos-vault/

• 备份配置文件：
  cp -a /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak
• 修改CentOS-Base.repo文件，取消baseurl开头的行的注释，并增加mirrorlist开头的行的注释。将文件中的http://mirror.centos.org替换成https://mirrors.huaweicloud.com，可以参考如下命令：
  sed -i "s/#baseurl/baseurl/g" /etc/yum.repos.d/CentOS-Base.repo
sed -i "s/mirrorlist=http/#mirrorlist=http/g" /etc/yum.repos.d/CentOS-Base.repo
sed -i "s@http://mirror.centos.org@https://repo.huaweicloud.com@g" /etc/yum.repos.d/CentOS-Base.repo

Page：https://mirrors.tuna.tsinghua.edu.cn/

使用说明
CentOS旧版本镜像地址为：https://mirrors.tuna.tsinghua.edu.cn/centos-vault/

• 备份配置文件：
  cp -a /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak
• 修改CentOS-Base.repo文件，取消baseurl开头的行的注释，并增加mirrorlist开头的行的注释。将文件中的http://mirror.centos.org替换成http://mirrors.tuna.tsinghua.edu.cn，可以参考如下命令：
  sed -i "s|#baseurl|baseurl|g" /etc/yum.repos.d/CentOS-Base.repo
sed -i "s|^mirrorlist=|#mirrorlist=|g" /etc/yum.repos.d/CentOS-Base.repo
sed -i "s|http://mirror.centos.org|https://mirrors.tuna.tsinghua.edu.cn|g" /etc/yum.repos.d/CentOS-Base.repo

RHEL使用CentOS源

※ 免责声明：以下内容仅作参考！

1. 删除RedHat自带的yum源
   查看：rpm -qa | grep ^yum
   删除：rpm -qa | grep yum | xargs rpm -e --nodeps
2. 下载CentOS镜像的yum包
   wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-3.4.3-158.el7.centos.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-rhn-plugin-2.0.1-10.el7.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-45.el7.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
3. 安装yum包提示“rpm >= 0:4.11.3-22 is needed by yum-3.4.3-158.el7.centos.noarch”
   rpm -qa | grep ^rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-4.11.3-32.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-libs-4.11.3-32.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-python-4.11.3-32.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-build-libs-4.11.3-32.el7.x86_64.rpm
rpm -Uvh rpm-*.rpm
4. 安装CentOS镜像的yum包
   rpm -ivh yum-*.rpm
5. 替换.repo文件中的$releasever版本为7
   sed -i "s/\$releasever/7/g" /etc/yum.repos.d/CentOS-Base.repo
6. 安装EPEL源
   yum install epel-release
7. 检查yum源可用性
   yum repolist && yum list all
8. yum update提示"Error: initscripts conflicts with redhat-release-server"
   yum check-update && yum update --skip-broken

吐槽：在RHEL 7.3系统上仅执行5,7,8步骤可以使用yum update，重装与不重装yum包都会提示“This system is not registered to Red Hat Subscription Management.”（CentOS 7.5 YUM源），可以跳过1,2,3,4步骤。

重建本地YUM缓存

• repo 文件下载链接，CentOS-7包含epel源
  centos6-aliyun.repo
  centos7-epel-aliyun.repo
  centos6-huaweicloud.repo
  centos7-epel-huaweicloud.repo
• 清理本地YUM缓存
  yum clean all && yum makecache

CentOS Mirror Status

http://mirror-status.centos.org/

从镜像状态统计来看，“华为开源镜像站、阿里巴巴开源镜像站”实时更新良好。