Signifying a formless haze of computing power and storage that is somewhere "out there," computerdom's current buzzword is as difficult to get one's arms around as a real cloud. A seemingly limitless pool of processors and memory and disk space, and you just scoop out what you need. Sounds great, doesn't it?

Of course, it's not that simple. You don't just grab a handful of virtual computers and toss them after your data. They have to be configured. If you need an n-tier system, you'll have to assemble the virtual networking components to tie them all together. In short, managing a herd of virtual systems in the cloud is no less difficult than managing a herd of physical computers.

[ Is your head in the clouds? Don't be fooled. See InfoWorld's Busting the nine myths of cloud computing and What cloud computing really means. ]

The four products in this roundup are designed to simplify the life of a cloud-based virtual-machine wrangler. To varying degrees, and in varying environments, each provides tools for creating, deploying, and managing collections of cloud-machines.

The products are the AppLogic platform from 3tera, the Elastic Computing Platform (ECP) from Enomaly, the Infrastructure and Middleware on Demand (IMOD) system from Kaavo, and RightScale, from the company of the same name. The 3tera and Enomaly offerings are tools for building your own private or hosted clouds. The Kaavo system works with third-party cloud services such as Amazon EC2. And RightScale works with both private clouds and third-party cloud services.

3tera AppLogic

The 3tera AppLogic system is its own cloud. That is, you do not run it on a third-party cloud provider such as Amazon EC2; you run it on hardware hosted by 3tera, or you provide the hardware and 3tera builds the cloud. AppLogic is referred to as a "meta-operating system." At its heart, it is Red Hat Linux running a specially configured Xen hypervisor. More precisely, it is a cluster of interconnected systems running Red Hat Linux, Xen, and the AppLogic orchestration system.

AppLogic can run on a remarkably spare piece of hardware. Minimum requirements are a 1GHz processor, 512MB of RAM, and 80GB of disk storage. Of course, this is the barest of beginnings; a single backbone of an AppLogic system can consist of up to 128 machines, and backbones can be combined to form overall networks of thousands of machines. Assuming you don't have the space in your basement for your own AppLogic system, 3tera already has datacenters in North America, South America, Europe, Japan, and Singapore. (Quantities and locations are changing; you should check 3tera's Web site for the latest details.)