What would be a good Orchestration tool for Triggering tests in Virtual Machine? Basically I want to trigger multiple parallel VM's to run automated tests. The tool should also have queuing mechanism.
Microsoft Visual Studio's Lab Manager can do this, I keep meaning to play around with it myself because I am in need of the same thing. Since I have not had a chance to play around with it yet, I can't tell you how well it works, but here is a link to the main page with a bunch of other training and documentation links on it: http://msdn.microsoft.com/en-us/vstudio/ee712698
This is likely a pretty expensive option, however my company already has licenses for Visual Studio Ultimate and TFS, so for us it should be pretty easy and inexpensive.
If I get a chance to play with it, I will update this thread with additional pertinent information.
Your continuous integration server should be able to handle this, if you use one. For example, Jenkins and TeamCity are capable of launching generic jobs, and both have "VM" plugins to abstract away the fact that the system on which you are starting your job is even a VM. We use TeamCity + VMWare Fusion in our work and it is effective.