项目简介
EPEL(Extra Packages for Enterprise Linux) 是由 Fedora Special Interest Group 维护的 Enterprise Linux（RHEL、CentOS）中经常用到的包。

使用方法
下面以 Rocky Linux 9 为例讲解如何使用本镜像站的 epel 镜像。RHEL 及其他衍生发行版同样可用该方法。

首先从 Extras 里安装 epel-release：

dnf install epel-release
用如下命令自动替换：（修改自 https://github.com/tuna/issues/issues/687）

sed -e 's!^metalink=!#metalink=!g' \

-e 's!^#baseurl=!baseurl=!g' \
-e 's!https\?://download\.fedoraproject\.org/pub/epel!https://mirrors.tuna.tsinghua.edu.cn/epel!g' \
-e 's!https\?://download\.example/pub/epel!https://mirrors.tuna.tsinghua.edu.cn/epel!g' \
-i /etc/yum.repos.d/epel{,-testing}.repo

epel.repo 的修改结果如下：（仅供参考，不同版本可能不同）

[epel]
name=Extra Packages for Enterprise Linux $releasever - $basearch

It is much more secure to use the metalink, but if you wish to use a local mirror

place its address here.

baseurl=https://mirrors.tuna.tsinghua.edu.cn/epel/$releasever/Everything/$basearch/

metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-$releasever&arch=$basearch&infra=$infra&content=$contentdir

enabled=1
gpgcheck=1
countme=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-$releasever

[epel-debuginfo]
name=Extra Packages for Enterprise Linux $releasever - $basearch - Debug

It is much more secure to use the metalink, but if you wish to use a local mirror

place its address here.

baseurl=https://mirrors.tuna.tsinghua.edu.cn/epel/$releasever/Everything/$basearch/debug/

metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-$releasever&arch=$basearch&infra=$infra&content=$contentdir

enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-$releasever
gpgcheck=1

[epel-source]
name=Extra Packages for Enterprise Linux $releasever - $basearch - Source

It is much more secure to use the metalink, but if you wish to use a local mirror

place its address here.

baseurl=https://mirrors.tuna.tsinghua.edu.cn/epel/$releasever/Everything/source/tree/

metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-source-$releasever&arch=$basearch&infra=$infra&content=$contentdir

enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-$releasever
gpgcheck=1
由于无法同步，镜像站不包含 EPEL Cisco OpenH264 仓库（epel-cisco-openh264.repo），如果不需要可手动将其改为 enabled=0。

运行 dnf update 测试一下吧。