As a cloud administrator one would want to use static private IP address for their VMs running on Eucalyptus cloud.
Some of the workloads running inside the VM depends on the private IP address and it gets changed every time the VM is started.
These workloads can get benefited with static IP private address.
At some sites it has been seen that there is a strict security control in place with a fixed inventory maintained for IP addresses assigned to the Virtual Machines, these sites would need the private IP to be static for management and security perspective.
Currently AWS VPC provides private static IP address.