Problem scenario: You try to use yum commands. You get an error about "no repomd file" and the desired yum command does not work. What should you do?
If you are using Fedora Linux, run this command:
Look at the output of the above command to find the version of Fedora. Verify you are using a recent version of Fedora (released within the past two years). View the "Release Schedule" of this link to find the year your version of Fedora was released. If you are using a version that is a few years old, upgrade your Fedora version.
If you are using CentOS Linux, run this command:
yum update --disablerepo=epel\*
Then run your yum command(s).