【linux】提示已加载插件：fastestmirror Loading mirror speeds from cached hostfile Could not retrieve……”

问题提示

系统在yum安装时弹出以下提示

sudo yum update -y
已加载插件：fastestmirror
 
Loading mirror speeds from cached hostfile
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

解决方案

删除原有的文件：

rm -f /etc/yum.repos.d/CentOS-Base.repo

然后重新下载阿里的：

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

清理缓存：

yum clean all

备用方案

ps:如果上述方法没有解决，尝试下面：

删除yum.repos.d目录下所有文件

rm -f /etc/yum.repos.d/*

然后重新下载阿里的：

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

清理缓存：

yum clean all

测试下载安装：

yum install gcc

完成！