Abstract: Embodiments disclosed herein utilize Habitats to perform incremental updates on virtual machines (VMs) over time. A VM Habitat comprises a collection of VMs and a specification shared between these VMs. Each Habitat specification may define an image name, processing power, etc. A Habitat specification may exist across a cluster of servers. In some embodiments, to dynamically update a Habitat specification, only “spare” VMs in the Habitat are updated, subject to some scheduling parameters and server concurrency limit. As spare VMs are updated, they move towards the new Habitat specification. Eventually, all VMs reach this goal over time, given sufficient spare VM resources. This approach can allow the service provided by the VMs to remain operational, thus maintaining the service level required for its users. This automated process can also eliminate or otherwise reduce human error either in the server removal/insertion from/to the cluster or in the VM update itself.

Abstract: A system providing methodology for policy-based resource allocation is described. In one embodiment, for example, a system for allocating computer resources amongst a plurality of applications based on a policy is described that comprises: a plurality of computers connected to one another through a network; a policy engine for. specifying a policy for allocation of resources of the plurality of computers amongst a plurality of applications having access to the resources; a monitoring module at each computer for detecting demands for the resources and exchanging information regarding demands for the resources at the plurality of computers; and an enforcement module at each computer for allocating the resources amongst the plurality of applications based on the policy and information regarding demands for the resources.