出现：

Cannot retrieve metalink for repository: epel/x86_64. Please verify its path and try again错误。

根据教程更改repo后报错：

failure: repodata/repomd.xml from epel: [Errno 256] No more mirrors to try. http://download.fedoraproject.org/pub/epel/7/x86_64/repodata/repomd.xml: [Errno 14] curl#6 - "Could not resolve host: download.fedoraproject.org; Unknown error"

是因为环境连不上epel，故卸载可解决：

$ rpm -qa | grep epel
epel-release-7-11.noarch
$ yum remove epel-release-7-11.noarch

参考链接：

https://www.cnblogs.com/netflix/p/12199694.html