解决yum安装时出现：Cannot retrieve metalink for repository: epel. Please verify its path and try again

在CentOS 7.6.1810 x64下安装glibc-2.17-260.el7_6.5.x86_64的时候出现了问题：Error: Cannot retrieve metalink for repository: epel. Please verify its path and try again，需要安装epel源。

解决方法： 把/etc/yum.repos.d/epel.repo，文件第3行注释去掉，把第四行注释掉。具体如下：

打开/etc/yum.repos.d/epel.repo，将

[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
#baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch

修改为

[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch

再清理源，重新安装

yum clean all
yum install -y 需要的包

如果还是不行，修改DNS,到/etc/resolv.conf下添加如下：

nameserver 8.8.8.8
search localdomain

然后重启network服务：service network restart