引

CentOS 7 系统无法连接到 CentOS 的官方镜像站点。这通常是由于网络问题或 CentOS 7 已停止维护导致的（2024年6月30日后 CentOS 7 已进入 EOL）

报错明细：

已加载插件：fastestmirror
Determining fastest mirrors
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was
14: curl#6 - “Could not resolve host: mirrorlist.centos.org; 未知的错误”
One of the configured repositories failed (未知),
and yum doesn’t have enough cached data to continue. At this point the only
safe thing yum can do is fail. There are a few ways to work “fix” this:
1. Contact the upstream for the repository and get them to fix the problem.
2. Reconfigure the baseurl/etc. for the repository, to point to a working
upstream. This is most often useful if you are using a newer
distribution release than is supported by the repository (and the
packages for the previous distribution release still work).
3. Run the command with the repository temporarily disabled
yum --disablerepo= …
4. Disable the repository permanently, so yum won’t use it by default. Yum
will then just ignore the repository until you permanently enable it
again or use --enablerepo for temporary usage:
yum-config-manager --disable
or
subscription-manager repos --disable=
5. Configure the failing repository to be skipped, if it is unavailable.
Note that yum will try to contact the repo. when it runs most commands,
so will have to try and fail each time (and thus. yum will be be much
slower). If it is a very temporary problem though, this is often a nice
compromise:
yum-config-manager --save --setopt=.skip_if_unavailable=true
Cannot find a valid baseurl for repo: base/7/x86_64

更新yum源

备份原有源

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

创建新的源文件

cat > /etc/yum.repos.d/CentOS-Base.repo <<'EOF'
[base]
name=CentOS-7 - Base
baseurl=https://vault.centos.org/7.9.2009/os/x86_64/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=1

[updates]
name=CentOS-7 - Updates
baseurl=https://vault.centos.org/7.9.2009/updates/x86_64/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=1

[extras]
name=CentOS-7 - Extras
baseurl=https://vault.centos.org/7.9.2009/extras/x86_64/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=1
EOF

清理并重建缓存

yum clean all
yum makecache