yum groupinstall is failing

Hello,

I am using Centos 7.1 The yum groupinstall commands are failing. As root I did a

yum group list

command. This returned various output with the following: "There is no
installed groups file."

Is it possible for yum groupinstall to work without a groups file? I
think my systems administrator won't allow me to install such a file.
If it is mandatory for yum groupinstall, how do I install a groups
file?

Does this command make irreversible changes?

yum groups mark convert

I want to try it.  But I am working on a production server.

thanks,

Mike