1. 进入配置目录

cd /etc/yum.repos.d/

2. 备份配置文件

cp CentOS-Base.repo CentOS-Base.repo.bak

3. 配置新 yum 源

3.1. 下载阿里云 YUM 源配置文件

curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-6.10.repo

4. 清理并重建缓存

4.1. 清理旧缓存

yum clean all

4.2. 删除缓存目录（可选）

rm -rf /var/cache/yum/

4.3. 重建缓存

yum makecache

5. 验证配置

yum repolist

6. 测试安装软件

yum install vim

7. CentOS 7 将 YUM 源切换到 vault.centos.org

7.1. 备份配置文件

sudo mkdir -p /etc/yum.repos.d/backup
sudo mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/backup/

7.2. 创建新的 CentOS-Base.repo 指向 vault

cat <<EOF | sudo tee /etc/yum.repos.d/CentOS-Base.repo
[base]
name=CentOS-\$releasever - Base
baseurl=https://vault.centos.org/centos/7.9.2009/os/\$basearch/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

[updates]
name=CentOS-\$releasever - Updates
baseurl=https://vault.centos.org/centos/7.9.2009/updates/\$basearch/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

[extras]
name=CentOS-\$releasever - Extras
baseurl=https://vault.centos.org/centos/7.9.2009/extras/\$basearch/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

[centosplus]
name=CentOS-\$releasever - Plus
baseurl=https://vault.centos.org/centos/7.9.2009/centosplus/\$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF

7.3. 清理并重建 YUM 缓存

sudo yum clean all
sudo rm -rf /var/cache/yum
sudo yum makecache

7.4. 测试安装或更新

sudo yum update

或

sudo yum install vim