Status code: 404 for http://mirrors.aliyun.com/centos/20/BaseOS/x86_64/os/repodata/repomd.xml (IP: 182.140.130.238)

回答: 根据引用\[1\]和引用\[2\]的内容，你遇到的问题是在下载CentOS的元数据时出现了404错误。这个错误表示无法找到指定的文件。具体来说，错误信息中显示的URL是https://mirrors.aliyun.com/centos/8/BaseOS/x86_64/os/repodata/repomd.xml，但是该URL返回了404状态码，表示文件不存在。同样的情况也出现在http://mirrors.cloud.aliyuncs.com/centos/8/AppStream/x86_64/os/repodata/repomd.xml这个URL上。根据引用\[3\]的内容，解决这个问题的方法是下载新的CentOS-Base.repo文件并替换原来的文件。你可以使用以下命令下载新的CentOS-Base.repo文件：
wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo
这样就可以解决你遇到的404错误了。
#### 引用[.reference_title]
- *1* [阿里云centos yum报错 - Status code: 404 for https://mirrors.aliyun.com/centos/centos/8/AppStream/x86_...](https://blog.csdn.net/weixin_42325823/article/details/122839554)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^insertT0,239^v3^insert_chatgpt"}} ] [.reference_item]
- *2* [- Status code: 404 for http://mirrors.cloud.aliyuncs.com/centos/8/AppStream/x86_64/os/repodata/repom](https://blog.csdn.net/will_net/article/details/124458114)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^insertT0,239^v3^insert_chatgpt"}} ] [.reference_item]
- *3* [Centos8 yum 下载元数据失败 Status code: 404 for https://mirrors.aliyun.com/centos/8/BaseOS](https://blog.csdn.net/qq_51663706/article/details/123234943)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^insertT0,239^v3^insert_chatgpt"}} ] [.reference_item]
[ .reference_list ]