Loaded plugins:fastestmirror, langpacks Loading mirror speeds from cached fastestmirror 宝塔

已加载插件：fastestmirror, langpacks Loading mirror speeds from cached hostfile Could not retrieve mirrorl

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Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&re      po=os&infra=stock error was
14: curl#7 – "Failed to connect to 2604:1580:fe02:2::10: 网络不可达"

 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

遇到这种情况有两种做法：

1、没网或者dns配置不正确，然后：ping www.qq.com

如果显示没有连接的话，就说明没网，也就无法使用yum 命令。

2、ping通了的话，还是是用不了yum命令，说明是yum镜像没有了，那么就得下载一个来更新。

在安装完CentOS后一般需要修改yum源，才能够在安装更新rpm包时获得比较理想的速度。国内比较快的有163源、sohu源。这里以163源为例子。

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