problem description

gdb debug the debug version of the program on centos 7 32bit, prompt the following:

[Inferior 1 (process 5470) exited with code 0315]
Missing separate debuginfos, use: debuginfo-install glibc-2.17-196.el7.i686 libgcc-4.8.5-16.el7_4.2.i686 libstdcPP-4.8.5-16.el7_4.2.i686

when executing debuginfo-install glibc-2.17-196.el7.i686 libgcc-4.8.5-16.el7_4.2.i686 libstdcPP-4.8.5-16.el7_4.2.i686 or yum install epel-release, the following error is prompted:

Loaded plugins: fastestmirror, langpacks
base                                                                                                                                                                  | 3.6 kB  00:00:00     
epel/i386/metalink                                                                                                                                                    |  47 kB  00:00:00     
Could not parse metalink https://mirrors.fedoraproject.org/metalink?repo=epel-7&arch=i386 error was 
No repomd file


 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:
 ......

the platform version of the problem and what methods you have tried

try yum clean and then yum update, has no effect

could you tell me how to solve this situation?