Cannot retrieve metalink for repository: epel/x86_64. Please verify its path and try again 问题分析

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

Loaded plugins: fastestmirror
 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. 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 retrieve metalink for repository: epel/x86_64. Please verify its path and try again

  今天在使用yum安装软件时遇到了如上报错，提示信息发现提示我epel源有问题，但是经过和可以安装的主机epel源的对比，发现并没有差别，所以问题肯定不在epel源配置文件上，所以就需要分析环境上的差异了，这台云主机是一台纯内网服务器，使用yum安装是通过使用了公网云主机的tinyproxy代理，而且使用curl命令测试连接网站没问题，也就是当前代理还在生效中，epel源就是使用yum命令安装的，所以yum也没问题，解决办法以及配置写到下面：

vim /etc/profile

export http_proxy=http://192.168.1.1:2525
export https_proxy=https://192.168.1.1:2525

  报错的原因是我在使用tinyproxy代理时，本地配置http全局代理，但是没添加https协议的代理，所以出现了以上的报错，添加https协议代理后，yum可以正常安装。