This is a bit of pain when you are using VMware and Ubuntu as every time there is a MAC address change udev will create another adapter i.e. eth0 will become eth1 and eth0 will seem to disappear. To stop this behaviour add this:

ENV{MATCHADDR}=="00:0c:29:*|00:50:56:*", ENV{MATCHADDR}=""

To the following file /lib/udev/rules.d/75-persistent-net-generator.rules