Reduced downtime migration of virtualized software services

A method, comprising:

• establishing a migrated instance of a software service in a virtualized environment having at least a portion of main memory of the virtualized environment mapped to a file within a block device instantiated for the virtualized environment;
• and
• directing the block device to reference a pre-migrated block device coupled over a network link to resume a state of an initial instance of the software service using contents of the pre-migrated block device corresponding to at least main memory of the initial instance of the software service.

The method of claim 20, comprising:

• responsive to initiating the migrated instance, transferring, to the file within the block device of the migrated instance, un-migrated contents of at least the main memory of the initial instance.

The method of claim 20, comprising:

• performing a live migration comprising:
• providing service to a client node from the software service at the initial instance until at least the block device references the pre-migrated block device, and responsively, providing additional service to the client node from the software service at the migrated instance.

The method of claim 20, comprising:

• migrating network addressing properties of the initial instance with respect to the migrated instance such that a client node retains a destination network address associated with the software service at the initial instance to communicate with the software service at the migrated instance.

The method of claim 20, comprising:

• mapping the portion of the main memory of the migrated instance to the file within the block device with at least an mmap kernel function for a hypervisor managing the virtualized environment of the migrated instance to synchronize at least the portion of the main memory of the migrated instance to the file.

The method of claim 20, comprising:

• mapping the main memory of the initial instance to an initial file within an initial block device with at least an mmap kernel function for a hypervisor managing the virtualized environment of the initial instance to synchronize at least the main memory of the initial instance to the initial file;
• and
• pre-migrating contents of the initial file to the pre-migrated block device over an initial network interface.

The method of claim 20, comprising:

• directing the block device to reference the pre-migrated block device by at least establishing a network block device mapped over the network link.

The method of claim 20, comprising:

• responsive to initiating the migrated instance, buffering intervening traffic received from a client node for the software service at the initial instance during at least migrating of network addressing properties of the initial instance to the migrated instance;
• and
• responsive to migrating the network addressing properties of the initial instance to the migrated instance, transferring the intervening traffic to the migrated instance with updated network destination addressing properties associated with the migrated instance.

The method of claim 20, wherein the software service comprises a further virtualized environment nested within the virtualized environment of the initial instance or the virtualized environment of the migrated instance.