CentOS7不再被维护以后, 这些问题是不是也在困扰着你?

首先, yum源问题

常见的错误

已加载插件：fastestmirror, langpacks
Determining fastest mirrors
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=extras&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=<repoid> ...

     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 <repoid>
        or
            subscription-manager repos --disable=<repoid>

     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=<repoid>.skip_if_unavailable=true

Cannot find a valid baseurl for repo: extras/7/x86_64

解决方法

这个错误通常是由于无法解析 CentOS 镜像站点造成的。你可以尝试以下几个步骤来解决：

1. 检查网络连接：确保你的服务器可以访问互联网。

2. 更新 DNS 配置：尝试使用公共 DNS，例如 Google 的 8.8.8.8。在 /etc/resolv.conf 中添加以下内容：

   nameserver 8.8.8.8 
   nameserver 8.8.4.4

3. 手动配置仓库：编辑 /etc/yum.repos.d/CentOS-Base.repo，检查 baseurl 是否正确，或者将其更改为具体的镜像地址。例如：

   baseurl=http://vault.centos.org/7.9.2009/os/$basearch/

   完整的CentOS-Base.repo内容为:

   # 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.
   #
   #
   
   [base]
   name=CentOS-$releasever - Base
   baseurl=http://vault.centos.org/7.9.2009/os/$basearch/
   gpgcheck=1
   gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
   
   #released updates 
   [updates]
   name=CentOS-$releasever - Updates
   baseurl=http://vault.centos.org/7.9.2009/updates/$basearch/
   gpgcheck=1
   gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
   
   #additional packages that may be useful
   [extras]
   name=CentOS-$releasever - Extras
   baseurl=http://vault.centos.org/7.9.2009/extras/$basearch/
   gpgcheck=1
   gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
   
   #additional packages that extend functionality of existing packages
   [centosplus]
   name=CentOS-$releasever - Plus
   mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus&infra=$infra
   #baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/
   gpgcheck=1
   enabled=0
   gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

4. 清理缓存：运行 yum clean all，然后再次尝试安装你所想要安装的工具和软件即可.