首先，切换国内YUM源的具体步骤取决于您使用的Linux发行版和当前的YUM源配置。以下是一般步骤，适用于大多数基于Red Hat的发行版，如CentOS和Fedora：

一、备份现有YUM源

在修改YUM源之前，建议先备份现有的YUM源配置文件，以防万一出现错误导致无法正常使用YUM

[root@hcss-ecs-c0a1 nginx]# mv /etc/yum.repos.d/CentOS-Linux-BaseOS.repo /etc/yum.repos.d/CentOS-Linux-BaseOS.repo.bak

二、下载新的YUM源配置文件

从官方网站或其他可靠的源下载新的YUM源配置文件。例如，如果您想要使用阿里云的YUM源。这里使用的是华为YUM源，因为我使用的是华为荣耀云服务，更新时相对较快。小伙伴们可以根据实际情况选择。

[root@hcss-ecs-c0a1 nginx]# wget -O /etc/yum.repos.d/CentOS-Linux-BaseOS.repo https://mirrors.huaweicloud.com/repository/conf/CentOS-8-anon.repo
--2024-06-23 14:50:33--  https://mirrors.huaweicloud.com/repository/conf/CentOS-8-anon.repo
Resolving mirrors.huaweicloud.com (mirrors.huaweicloud.com)... 124.70.125.167, 124.70.125.153
Connecting to mirrors.huaweicloud.com (mirrors.huaweicloud.com)|124.70.125.167|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/octet-stream]
Saving to: ‘/etc/yum.repos.d/CentOS-Linux-BaseOS.repo’

/etc/yum.repos.d/CentOS-Linux-BaseOS.repo           [ <=>                                                                                                 ]   2.21K  --.-KB/s    in 0s      

2024-06-23 14:50:33 (49.6 MB/s) - ‘/etc/yum.repos.d/CentOS-Linux-BaseOS.repo’ saved [2263]
[root@hcss-ecs-c0a1 nginx]# cat /etc/yum.repos.d/CentOS-Linux-BaseOS.repo
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the 
# remarked out baseurl= line instead.
#
#
 
[BaseOS]
name=CentOS-$releasever - Base - mirrors.huaweicloud.com
baseurl=https://mirrors.huaweicloud.com/centos-vault/8.5.2111/BaseOS/$basearch/os/
#mirrorlist=https://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=BaseOS&infra=$infra
gpgcheck=1
gpgkey=https://mirrors.huaweicloud.com/centos/RPM-GPG-KEY-CentOS-Official
 
#released updates 
[AppStream]
name=CentOS-$releasever - AppStream - mirrors.huaweicloud.com
baseurl=https://mirrors.huaweicloud.com/centos-vault/8.5.2111/AppStream/$basearch/os/
#mirrorlist=https://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=AppStream&infra=$infra
gpgcheck=1
gpgkey=https://mirrors.huaweicloud.com/centos/RPM-GPG-KEY-CentOS-Official

[PowerTools]
name=CentOS-$releasever - PowerTools - mirrors.huaweicloud.com
baseurl=https://mirrors.huaweicloud.com/centos-vault/8.5.2111/PowerTools/$basearch/os/
#mirrorlist=https://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=PowerTools&infra=$infra
gpgcheck=1
gpgkey=https://mirrors.huaweicloud.com/centos/RPM-GPG-KEY-CentOS-Official


#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - mirrors.huaweicloud.com
baseurl=https://mirrors.huaweicloud.com/centos-vault/8.5.2111/extras/$basearch/os/
#mirrorlist=https://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
gpgcheck=1
gpgkey=https://mirrors.huaweicloud.com/centos/RPM-GPG-KEY-CentOS-Official


#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - mirrors.huaweicloud.com
baseurl=https://mirrors.huaweicloud.com/centos-vault/8.5.2111/centosplus/$basearch/os/
#mirrorlist=https://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
gpgcheck=1
enabled=0
gpgkey=https://mirrors.huaweicloud.com/centos/RPM-GPG-KEY-CentOS-Official

---

-O：这是一个选项，它告诉wget将下载的文件输出到指定的文件名。在这里，-O后面跟着的路径是/etc/yum.repos.d/CentOS-Base.repo，这是YUM仓库配置文件的路径

---

需要其他源的可以去https://mirrors.huaweicloud.com/repository找，很方便

三、先清理YUM缓存再生成

[root@hcss-ecs-c0a1 nginx]# yum clean all
6 files removed
[root@hcss-ecs-c0a1 nginx]# yum makecache
CentOS-8 - Base - mirrors.huaweicloud.com                                                                                                                    3.3 MB/s | 4.6 MB     00:01    
CentOS-8 - AppStream - mirrors.huaweicloud.com                                                                                                               664 kB/s | 8.4 MB     00:13    
CentOS-8 - PowerTools - mirrors.huaweicloud.com                                                                                                              800 kB/s | 2.3 MB     00:02    
CentOS-8 - Extras - mirrors.huaweicloud.com                                                                                                                   35 kB/s |  10 kB     00:00    
Extra Packages for Enterprise Linux 8 - x86_64                                                                                                                                                
Extra Packages for Enterprise Linux Modular 8 - x86_64                                                                                                                                        
Metadata cache created.
[root@hcss-ecs-c0a1 nginx]# 

四、测试新的YUM源

[root@hcss-ecs-c0a1 nginx]# yum install epel-release
Last metadata expiration check: 0:12:18 ago on Sun 23 Jun 2024 03:05:27 PM CST.
Package epel-release-8-19.el8.noarch is already installed.
Dependencies resolved.
Nothing to do.
Complete!
[root@hcss-ecs-c0a1 nginx]# 

如果安装成功，说明新的YUM源配置正确。

五、重启系统服务(生效可以不重启)可选

systemctl restart network.service
systemctl restart yum.service

提示
本人以抱着学习的态度去分享，以上内容如有雷同，不胜荣幸！如有不足，欢迎评论留言！