Changes for supporting fast cloning on Xenserver.

Implements blueprint fast-cloning-for-xenserver
	1. use_cow_images flag is reused for xenserver to check if copy on write images should be used.
	2. image-id is used to tag an image which has already been streamed from glance.
	3. If cow is true, when an instance of an image is created for the first time on a given xenserver, the image is streamed from glance and copy on write disk is created for the instance.
	4. For subsequent instance creation requests (of the same image), a copy on write disk is created from the base image that is already present on the host.
	5. If cow is false, when an instance of an image is created for the first time on a host, the image is streamed from glance and its copy is made to create a virtual disk for the instance.
	6. For subsequent instance creation requests, a copy of disk is made for creating the disk for the instance.
	7. Snapshot creation code was updated to handle cow=true. Now there can be upto 3 disks in the chain. The base disk needs to be uploaded too.
	8. Also added a cache_images flag. Depending on whether the flag is turned on on not, images will be cached on the host.

Change-Id: I54838a24b061c134877f3479c925c6ee78da14bc

1 files changed, 1 insertions, 0 deletions

diff --git a/Authors b/Authors
index afcc2bd70b..4df821419f 100644
--- a/Authors
+++ b/Authors
@@ -43,6 +43,7 @@ David Subiros <david.perez5@hp.com>
 Dean Troyer <dtroyer@gmail.com>
 Deepak Garg <deepak.garg@citrix.com>
 Derek Higgins <higginsd@gmail.com>
+Devdeep Singh <devdeep.singh@citrix.com>
 Devendra Modium <dmodium@isi.edu>
 Devin Carlen <devin.carlen@gmail.com>
 Donal Lafferty <donal.lafferty@citrix.com>