[root@bogon ~]# yum install nginx

Loaded plugins: fastestmirror

Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast

base                                                                                            | 3.6 kB  00:00:00

epel/x86_64/metalink                                                                            | 4.5 kB  00:00:00

epel                                                                                            | 4.4 kB  00:00:00

http://mirrors.ustc.edu.cn/fedora/epel/7/x86_64/repodata/repomd.xml: [Errno -1] repomd.xml does not match metalink for epel

Trying other mirror.

epel

#------------------------------------------------------------------------

解决方法：

#yum   update