To disable Consistent Network Device naming in CoreOS, run

ln -s /dev/null /etc/udev/rules.d/80-net-setup-link.rules

Then reboot the server

reboot

Now network interface will look like

core@localhost ~ $ ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0:  mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:16:3c:9f:d1:dc brd ff:ff:ff:ff:ff:ff
    inet 198.204.228.181/24 brd 198.204.228.255 scope global dynamic eth0
       valid_lft 21599936sec preferred_lft 21599936sec
    inet6 fe80::216:3cff:fe9f:d1dc/64 scope link 
       valid_lft forever preferred_lft forever
core@localhost ~ $ 

• Ubuntu disable Consistent Network Device Naming