I run a budget-less Hudson cluster, just like many of you do, and one of the challenges is to have enough computing resources in a cluster. I rely on recycled computers as the main workhorse, so I constantly look for unused computers under people's desks, and when people give them to me, I reinstall them as Hudson slaves.

In this process, I learned a lesson; people don't like to be separated from their computers, even long after they stopped using them, because they think they might occasionally need them in the future, or they may later discover that they forgot to copy some data to their new computers. That is, what's really happening is that the idea of your computer getting reformatted makes them nervous, and that is entirely understandable — if you'll never see it again, you better darn sure that you won't never ever need it, right?

Therefore, a better approach is to let them keep the computers, and instead ask them to run a slave as a virtual machine. Even better, such a set up would even let me ask them to run the VM on their newer computers, too, because it's very easy to see that a VM won't jeopardize their systems. With a little bit of VirtualBox Python API programming, I can make it so that the VM only runs when no one else is logging in, by using the memory and virtual disk that are proportional to the host system.

Or you can take this even further and just login to all the machines on the network, and just start a VM everywhere you can.

Toward that goal, I released the Hudson swarm slave plugin. This plugin comes with a little CLI agent, which uses a UDP broadcast to discover a nearby Hudson master, that's equipped with the Hudson swarm plugin. It then hooks up the slave on the fly, and joins the cluster, then Hudson will start running builds and tests on this swarm CLI agent.

With the recent improvements in Hudson to automatically install JDKs, Ants, and Mavens from the network, this instantly turns a plain-vanilla PC into a working Hudson slave, without administrators manually registering the new slave. I think this opens up a whole new way of creating a Hudson cluster, in a somewhat self-organizing fashion.

So there, Mahesh, that's how I plan to recruit your 3 beautiful Sun workstations with Core 2 Extreme CPUs. I know you are not really using them... :-)