I accidentally removed my Python's site-packages which means I got no any modules. Unfortunately, I noticed too late that the Yum uses a module named yum which is installed in the Python's site-packages where is located in /usr/local/lib/python2.7/site-packages.
I was trying to reinstall yum but no yum module was installed.
Hope to find an answer,
thanks!
I fixed this issue by installing CentOS on a VM and then scp the python2.7 directory to the server.
Centos 7 - No module named yum - Accidentally removed Python site-packages