Linux how to find which yum package to install..

If you are sure about the location of the executable, than you can make yum, search the packages that uses the same executable.

yum provides /usr/sbin/semanage

My output:
 ......
base                                                     | 3.7 kB     00:00    
extras                                                   | 3.0 kB     00:00    
updates                                                  | 3.5 kB     00:00    
policycoreutils-python-2.0.83-19.24.el6.i686 : SELinux policy core python.....

So after finding out the package, now it is time to install it..

yum -y install policycoreutils-python