I'm seeing a similar issue on Ubuntu 14.04 and Kilo 2015.1.4.
A VM with multiple interface loses connectivity after a rebuild or a shut off start.
One interface has floating-ip on which should be on eth0 the others are for other communicaton (internal). After a rebuild an internal interface gets the eth0 position and VM can not be reached with floating-ip.
I'm seeing a similar issue on Ubuntu 14.04 and Kilo 2015.1.4.
A VM with multiple interface loses connectivity after a rebuild or a shut off start.
One interface has floating-ip on which should be on eth0 the others are for other communicaton (internal). After a rebuild an internal interface gets the eth0 position and VM can not be reached with floating-ip.