CentOS ties your ethernet interfaces to their MAC addresses. This is problematic
when using CentOS in a virtualized environment, because it ends up preserving
old ethernet interfaces. Fortunately, there is a quick fix.
ifconfig only shows eth1 - where is eth0?
Remove the files that have eth0’s hardware address and UUID, and then reboot.
If using templates, run this command, shut down, and then create the template
Alternatively, edit ifcfg-eth0 and remove the lines with MAC and UUID.