Clonable and space-efficient images of running VMs for fast provisioning on IaaS cloud platforms

It is critical to minimize the time for provisioning the virtual
machines (VMs) in the cloud environment, particularly
because more dynamic deployment of cloud workloads, such
as Hadoop jobs and auto scaling of Web servers, is becoming
popular. Provisioning consists of transferring a disk image
of the operating system and the target application from the
image repository to a disk of the host machine and booting
the VM from the disk to the memory of the host machine.
If we can preload (cache) the disk images of popular
(frequently-used) operating systems and applications as the
base images at each host machine in advance and maintain
the delta (only the updated part of the selected base image)
as we go, we can greatly reduce the time for transferring
and the disk space. To that end, we propose to use the
copy-on-write snapshot mechanism of logical volume manager
of Linux. Furthermore, if we can save the memory
image of the VM from the host machine to the image repository
when we shutdown the VM, we can greatly reduce its
booting time when we resume it on a different host machine
for the next time. To that end, we propose to use the hibernation
mechanism of Xen hypervisor. With these two
proposed techniques, we have successfully achieved 28X and
8X speedup in provisioning a single VM and 64 VMs in our
experiment, respectively.