1. A method comprising: determining one or more overlay network attributes (ONAs) for a plurality of virtual networks; associating the one or more ONAs with the plurality of virtual networks; managing the one or more ONAs as one or more portable entities by one or more of creating ONAs, deleting ONAs, moving ONAs, combining ONAs and dividing ONAs; and performing a movement operation on the one or more virtual networks among one or more servers of one or more overlay networks based on the management of the one or more ONAs.