US Patent 9459856 Effective migration and upgrade of virtual machines in cloud environments

A mechanism is provided in a data processing system for performing a system upgrade. Responsive to receiving selection of one or more virtual machines to upgrade with an upgrade package, the mechanism identifies a plurality of upgrade phases. The mechanism configures the plurality of upgrade phases and generates a pre-upgrade snapshot of each of the one or more virtual machines. The mechanism performs each upgrade phase in the plurality of upgrade phases to form an upgraded virtual machine and performs one or more upgrade validation tests on the upgraded virtual machine. Responsive to the one or more upgrade validation tests succeeding, the mechanism reverts back to the pre-upgrade snapshot.