Predefined IPs should not be released when terminating the instances. Currently all the floating IPs accosiated with an instance will be released(deleted) when stratos terminates the instance.
This is a must feature, otherwise if we unsubscribe to a cartridge with predefined floating IP, we can't subscribe to it again as the floating IP is not there.
To see how we are going to implement this, have a look at "Stratos should not release(delete) predefined floating IPs?" mail thread in stratos dev list.