1. cd /etc/yum.repos.d
2. mv CentOS-Base.repo CentOS-Base.repo.backup
3. wget https://mirrors.aliyun.com/repo/Centos-vault-6.10.repo
4. mv Centos-vault-6.10.repo CentOS-Base.repo  
5.yum clean all

如果中间报wget的错  就要在Windows里面下载Centos-vault-6.10.repo包  然后用winscp上传到那个目录下然后 yum -y install wget  安装下wget

然后GPG key retrieval failed: [Errno 14] HTTP Error 404 - Not Found  又报错

执行下面这两条命令就可以直接 yum安装你想要安装的东西了

rpm --import /etc/pki/rpm-gpg/RPM*

rpm --import /etc/pki/rpm-gpg/RPM*

报错详细信息

Loaded plugins: fastestmirror
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was
14: HTTP Error 404 - Not Found

 One of the configured repositories failed (Unknown),
 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. Disable the repository, 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>

     4. 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: base/7/x86_64