dd到centos 7时遇到一个问题，发现里面那个网站已经502了，这里我贴一个日志，

[AndraidAP270868441b4]

/sbin/grubby cpe:/o:centos:centos:7 cat: /dev/ipv6_has_internet: No such file or directory cpe:/o:centos:centos:7 Loaded plugins: fastestmirror Determining fastest mirrors Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=genclo error was 14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"

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. 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: base/7/x86_64 Error: Line 2129 return 1 chroot /os/ yum -y --disablerepo=* --enablerepo=base,updates "$@"

[Spark100k]

可以使用vault.centos.org https://vault.centos.org/7.9.2009/os/x86_64/ https://vault.centos.org/7.9.2009/isos/x86_64/

如果必须使用centos7，Yum源也可以更换为vault继续使用， 先备份下默认源 cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup 使用官方vault源替换 sed -i -r -e 's|^mirrorlist=|#mirrorlist=|g' -e 's|^#?baseurl=http://mirror.centos.org/centos|baseurl=https://vault.centos.org/centos|g' -e 's|^#?baseurl=http://mirror.centos.org/altarch|baseurl=https://vault.centos.org/altarch|g' -e 's|^#?baseurl=http://download.fedoraproject.org|baseurl=http://download.fedoraproject.org|g' /etc/yum.repos.d/CentOS-*.repo

运行以下命令重新创建缓存。 yum clean all && yum makecache

国内机器可以修改使用aliyun源

[bin456789]

现已修复 但是centos7停止维护了 建议用 anolis 7