Announcing the first release of SnowFlock

[Andres Lagar-Cavilla <andreslc@cs.toronto.edu>]

Hi everyone,
we're releasing Snowflock to the general public. We're making a binary 
and source relase, under the GNU General Public License (GPL). The 
release is available at http://compbio.cs.toronto.edu/snowflock.

Briefly, Snowflock lets you clone Xen VMs into dozens of identical 
replicas running in different hosts. Snowflock can do this in less than 
a second and with very low runtime overhead. With Snowflock you can, for 
example, perform parallel computations on the fly by scaling 
"instantaneously" your computing footprint in a shared cluster. 
Snowflock is a research prototype, hence the 0.1 major-minor. A minimum 
degree of experience with Xen and Linux is necessary to use the system. 
The contact address for snowflock is snowflock-users@cs.toronto.edu

More technically:
Snowflock is our prototype implementation of the / Impromptu Cluster 
(IC)/ abstraction. In an IC, an application encapsulated inside a 
virtual machine (VM) is swiftly forked into multiple copies that execute 
on different physical hosts, and then disappear when the computation 
ends. ICs simplify the development of parallel applications and reduces 
management burden by enabling the instantiation of new stateful 
computing elements: workers that need no setup time because they have a 
memory of the application state achieved up to the point of forking. 
This approach combines the benefits of cluster-based parallelism with 
those of running inside a VM.

Snowflock provides swift parallel VM cloning that makes it possible for 
Internet applications to deliver near-interactive performance for 
resource-intensive highly-parallelizable tasks. Snowflock makes use of 
four key techniques: /VM descriptors/ (condensed VM images that allow 
for sub-second suspension of a running VM and resumption of a of 
replicas); a /memory-on-demand/ subsystem that lazily populates the VM's 
memory image during runtime; a set of / avoidance heuristics/ that 
minimize the amount of VM memory state to be fetched on demand; and a 
/multicast distribution/ system for commodity Ethernet networking 
hardware that makes the overhead of instantiating multiple VMs similar 
to that of instantiating a single one.

Use, enjoy, give us some feedback, and contribute to mankind :)
The Snowflock team