When Andrew and I built the esx.pm provisioning module that was developed at the Open Systems Collaboration and Research Lab (OSCaR), we wanted to build load balancing functionality based on feedback from the usage of the servers in real time. From our evaluation, there is not reasonable way to do this with the VCL 2.X architecture. The heart of the problem is that the 2.X architecture achieves scheduling through a combination of frontend code, backend code, and a database in the middle. The placement decision (which hypervisor an image will run on) is decided in the frontend, so no amount of API's will enable this decision to be more intelligent without rewriting portions of both the frontend and backend to being ESX aware and ESX specific. Over time, integrating a large number of resource types makes this integration path intractable.

Having tried to implement this into VCL 2.X, this feature use case is what brought about the proposal of an alternative VCL architecture to accommodate these types of features and extensions in a more reasonable way/ (found here: http://cwiki.apache.org/confluence/display/VCL/Experimental+VCL+Architecture+Document) . An implementation of this experimental architecture is nearing the proof of concept stage, and I will commit the POC code of the proposed experimental architecture to a branch of the SVN next week. I would encourage your team to use that as a starting point for the integration you propose. It could be done easily by rewriting the PlacementController component inside the ESX Resource Manager, which will contain a simple round robin scheduler as it goes to pair images with hypervisors to run on. More documentation will also be provided along with the initial code commit to help get you started.


Brian Bouterse
Secure Open Systems Initiative

On May 15, 2009, at 12:44 AM, 杨杰 wrote:

We are now trying to integrate VCL as a provision manager to a load
banlancing tool. The experiment may help us to manage the VMs according to
the server load automatically.

The task demands definite understand on the API of VCL, which will
considerably advance our experiment. How could i get it ? or is there any
website to view the API document ?

Thank you !

Yang Jie(杨杰)

Team of MRMSS, Xi'an Jiaotong University

Department of Computer Science and Technology, Xi’an Jiaotong University

TEL: +8613468883723;029-82665263 EXT.24

MSN: xtyangjie2...@yahoo.com.cn

E-mail: xtyang...@gmail.com
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