The easiest way to restore the old way Kernel/modules/udev rename your ethernet interfaces is supplying these kernel parameters to CentOS 7:
To do so follow this steps:
At the end of GRUB_CMDLINE_LINUX line append "net.ifnames=0 biosdevname=0"
Save the file
Type "grub2-mkconfig -o /boot/grub2/grub.cfg"
If you didn't supply these parameters during the installation, you will probably need to adjust and/or rename interface files at /etc/sysconfig/network-scripts/ifcfg-*.
Up to Fedora 18, just biosdevname=0 was enough.
As an example, in a certain machine, in a exhaustive research, I got:
-No parameters: NIC identified as "enp5s2".
-Parameter biosdevname=0: NIC identified as "enp5s2".
-Parameter net.ifnames=0: NIC identified as "em1".
-Parameter net.ifnames=0 AND biosdevname=0: NIC identified as "eth0".