1. A method for deploying a virtual machine (VM) on a plurality of hosts in a distributed computing environment, the method comprising: notifying at least one host from among a plurality of hosts to download a master copy of a VM image from a remotely located network storage device to a storage medium locally connected to the at least one host, in response to a service provider providing a definition manifest for a service request that is to be serviced by the VM, wherein the definition manifest is provided to a centralized site management unit that is in communication with the plurality of hosts in a communications network, wherein the centralized site management unit communicates at least part of the definition manifest to the at least one host to notify the host to download the master copy of the VM image, wherein the definition manifest provides predefined specifications on how to customize the VM to run on the host, so that the VM is able to service the service request, wherein the definition manifest further provides rules about when to deploy additional VMs on the host to service additional service request, wherein the host replicates a copy of the downloaded VM image in a local cache associated with the host so that the host customizes and deploys the VM directly from the locally replicated copy of the VM image, without having to modify the master copy of the VM image downloaded to the storage medium locally connected to the host, wherein deployment of the VM on the host allows the host to locally service the service request associated with the definition manifest, wherein the host replicates copies of the downloaded VM image in the local cache, by way of copy-on-write, to generate one or more VM clones; wherein the host customizes the one or more VM clones based on the definition manifest, wherein the copy-on-write process creates a pointer to the VM image in the local cache to create an instant VM clone of the VM image without actual copying of the VM image stored in the storage medium locally connected to the host, such that same VM image is shared among multiple VM clone instances without the need to shut down the VM's already deployed on the host.