Linux | Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x

报错：

Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock32 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. 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

解决办法：

1.检查是否可以上网

ping 114.114.114.114

如果不可以，调试通。通了之后下一步：

2.检查DNS设置是否正常

ping www.baidu.com

不正常的话，设置DNS，如下：

#vi /etc/resolv.conf

#nameserver 223.5.5.5
#nameserver 223.6.6.6
#nameserver 114.114.115.115

nameserver 114.114.114.144

保存后，重启服务或者机器，再次ping www.baidu.com或者下面连接。

ping mirrorlist.centos.org

通了即解决问题