yum源因为修改镜像源导致无法使用

报错信息：

[root@bigdata ~]# yum update
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.aliyun.com
 * extras: mirrors.huaweicloud.com
 * updates: mirrors.aliyun.com
http://mirrors.aliyun.com/epel/5/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not Found
正在尝试其它镜像。
To address this issue please refer to the below wiki article 

https://wiki.centos.org/yum-errors

If above article doesn't help to resolve this issue please use https://bugs.centos.org/.

 One of the configured repositories failed (Extra Packages for Enterprise Linux 5 - x86_64),
 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=epel ...

     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 epel
        or
            subscription-manager repos --disable=epel

     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=epel.skip_if_unavailable=true

failure: repodata/repomd.xml from epel: [Errno 256] No more mirrors to try.
http://mirrors.aliyun.com/epel/5/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not Found

我的解决方式：

第一步：cd /etc/yum.repos.d/下的文件先备份

第二步：找个yum好使的服务器，输入cd /etc/yum.repos.d/命令，进入此文件夹

第三步：将yum好用的服务器cd /etc/yum.repos.d/下的文件拷贝到不好用的服务器的cd /etc/yum.repos.d/下

第四步：分别执行yum clean all   yum makecache  yum update 命令

备注：

如果此方式没有解决大家的问题，请将您的解决方式发到评价栏，之后我再做更新（附带提供者名称）