that, at boot time, contacts the RightScale system and basically asks: "I just booted, what am I supposed to do?" The RightScale system then begins feeding the image whatever RightScripts it is configured to use. And, of course, the necessary scripting languages are pre-installed on RightScale images. For example, RightScale pre-installs Ruby; I was told by a RightScale engineer that they use Ruby "extensively." These modifications convert a basic machine image into a "RightImage."
Ultimately, a RightScript will end up as part of a ServerTemplate. A ServerTemplate is a base server image, associated with the RightScripts that configure the server to do its assigned work. For example, an Ubuntu-based MySQL ServerTemplate would consist of an Ubuntu machine image and all the RightScripts needed to install, configure, and launch MySQL. RightScale provides a number of prebuilt, application-specific ServerTemplates. To create your own, you merely clone a copy of the original, add or modify the associated RightScripts, and save the result in your local repository.
You control your RightScale-based systems via a Web-based management console. You begin at the Dashboard, from which you can view currently defined deployments -- a deployment being a collection of machine instances, typically working together for a single purpose. For example, an Apache Web server, Tomcat application server, and MySQL database server, combined to provide a shopping cart application, could be saved as your custom-built Shopping Cart Deployment.
Down the tool chain is the Management screen, for creating and configuring servers, arrays of servers (for those times when the number of servers must grow or shrink based on changing workloads), and deployments. Select a deployment from the list, and you can configure its internals, or launch it and monitor its status.
The console also has tools for managing important Amazon Web Services cloud resources such as SSH keys, security groups, and machine images. RightScale's console excels at context-sensitive help, as well as comprehensive onscreen documentation (that can be turned off, once you've become expert at the system).
RightScale offers five different editions, ranging from the free Developer's Edition to the feature-rich Enterprise Edition. Of course, the free edition includes no support and lacks add-ons available with the paid editions. The feature combinations of the various editions are extensive enough that you need a matrix to comprehend it all; such a matrix can be found on RightScale's Web site.
In the clouds
When it comes to cloud tools, one certainly cannot complain about the assortment. If you've already settled on Amazon EC2 as your cloud provider, then head on over to RightScale or Kaavo. If you'd prefer to build a cloud system yourself, check out 3tera or Enomaly.
The name of the game is the reduction of complexity. Configuring, launching, and monitoring a multitier cloud-based application is a process of many steps. There are OSes to choose, applications to install, connections to establish, security permissions to worry about, and on and on. And launching a multitiered system is an essentially asynchronous process; if something goes wrong, it is not altogether easy to figure out where the problem is. Each tool here tried to make that easier; each succeeds on different fronts to different degrees.
3tera's AppLogic excels at representing an n-tier system as a collection of interoperating applications, rather than a collection of interoperating virtual OSes running applications. Abstracting out the OS is a powerfully simplifying force.
Kaavo's user interface is well laid out and easy to navigate. It is impossible to get lost with Kaavo, and it's easy to figure out where in the UI you need to go to perform a particular task.
[ Stay on top of cloud developments from an IT professional's perspective in whurley's Cloud Computing blog. ]
RightScale's approach is finer-grained -- focusing on individual machine instances -- and more demanding of the cloud architect, but its abundance of pre-written RightScripts, in-line help, and copious examples goes a long way to lowering the learning curve. In addition, RightScale's RightGrid feature provides
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