一、镜像源修改

1. 备份原有的镜像源配置文件

在修改之前，先备份现有的 CentOS-Base.repo 文件：

sudo cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

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2. 编辑镜像源配置文件

使用文本编辑器（如 nano 或 vi）打开 /etc/yum.repos.d/CentOS-Base.repo 文件：

sudo vim /etc/yum.repos.d/CentOS-Base.repo

将文件内容替换为以下阿里云镜像源的配置：

# 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 pi