US Patent 10404579 Virtual machine instance migration using a hypervisor

Techniques for managing a critical phase of a virtual machine migration are described herein. During the critical phase, which must be kept as short as possible, a virtual machine instance is paused, network packets are rerouted to a temporary packet queue, and messages associated with managing synchronization of block storage devices are dispatched to an entity configured to manage those connections. After the block storage devices are synchronized, the network packets are released from the temporary packet queue to the new location of the virtual machine instance.