Cloud control systems tame the ether

3tera, Enomaly, Kaavo, and RightScale take myriad and mixed approaches to managing virtual servers in the sky

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Other entries on the control panel include the Profile tab, where you can configure your account. This tab also includes billing and user management. From the Accounting tab, you can review your service usage over a selectable time range.

IMOD's system definition file is a two-edged sword. On the one hand, it keeps everything in one place, and that bookkeeping advantage should not be underrated. Also, if something goes wrong, you pretty much know where to look. On the other hand, it's one more language's syntax you have to learn. Because it depends on Velocity, an understanding of Java is a definite advantage. Nevertheless, Kaavo's documentation is good enough that even new users can find their way around with few bruised noses.

If you want to go it on your own, Kaavo has a self-serve plan that begins with a 30-day free trial. After that, you pay a fixed monthly fee for a fixed number of CPU hours. Exceed the available hours, and you fall into a pay-as-you-go scheme for any additional time. Users who need guidance will want the Enterprise Solution, which provides 24/7 support and training; contact Kaavo for pricing. Currently, Kaavo supports only Amazon's EC2, but expects to add support for other cloud providers in the near future.

RightScale

RightScale takes a non-intuitive approach to preparing and managing cloud-based systems. Rather than preconfigure a machine image, the RightScale methodology is to launch a "bare" image and have that instance configure itself by executing pre-installed scripts. Such scripts are called RightScripts, and they are the essential ingredients of a RightScale-powered cloud system.

A RightScript can be written in any of the well-known scripting languages: shell script, Python, Perl, or Ruby, to name a few. The language is unimportant. What is important is the fact that RightScripts can include parameters, and those parameters can be programmatically filled in by the RightScale system at runtime. RightScripts are therefore reusable, so a RightScript that installs MySQL, for example, can work on any cloud server that needs a MySQL installation.

There are three types of RightScripts, each designed to run at a specific point in a machine image's lifetime. Boot RightScripts execute just after the machine image is booted. Operational RightScripts execute once the image is running. And a decommission RightScript will execute just prior to the image being shut down. RightScripts can be used for just about any operation imaginable, but typically they install, configure, and start applications on the machine image they occupy.

To be accurate, RightScale images aren't completely barren. First, RightScale images include a small piece of software 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 a prebuilt grid architecture for lashing together clusters of virtual machines in a "producer-consumer" structure, making it easy to build large-scale processing systems without getting bogged down in the details.

Finally, I can only recommend Enomaly's ECP for the technically savvy. The engineers at Enomaly were extremely helpful in answering questions, and I applaud any system based on open source technology. I would heavily encourage involvement in Enomaly's community edition. But the lack of substantial documentation and missing application configuration capabilities leaves me reluctant to advocate ECP for production deployment. A new release is expected this summer, and perhaps the added features will erase my doubts.

Cloud management systems

3tera AppLogic

Release: 2.4.8

Platforms: Private and hosted AppLogic clouds

Pros and cons:

+Graphical "wiring" of applications is easy to work with.

+Lots of pre-built applications.

+Application-centric view of system.

-ADL requires a modest learning curve.

-Built on proprietary AppLogic runtime system.

Bottom line: 3Tera's graphical user interface captures your application's architecture in an easy-to-manage form. Its treatment of components as appliances also simplifies system construction. But it locks you into 3Tera's AppLogic environment.

Enomaly ECP

Release: 2.2.3

Platforms: Private and hosted ECP clouds

Pros and cons:

+Built on open source technology.

+Freeware version available.

+Runs a variety of virtual machines.

-Documentation is seriously lacking.

-No visible tools for managing applications on target OSes.

Bottom line: You can't argue with Enomaly's price tag: free is as good as it gets. And you are not tied to any proprietary software or cloud infrastructures. But Enomaly has a way to go before deployment is as simple as with the other tools.

Kaavo IMOD

Release: 1.4.5

Platforms: Cloud service providers including Amazon EC2

Pros and cons:

+Excellent control panel UI.

+Graphical view of application is easy to manipulate.

+Lots of pre-built appliances.

-Currently only supports EC2.

-Some configuration steps not readily apparent.

Bottom line: Kaavo's bundling of an application's descriptive and executable information into a single System Definition file unclutters application management, and allows for easy transfer of an application from one installation to another. However, it does require study of the underlying XML and Velocity syntax.

RightScale

Release: April 21, 2009

Platforms: Private clouds and cloud service providers including Amazon EC2

Pros and cons:

+Excellent documentation.

+Free version available.

+Large selection of RightScripts and machine images.

-Machine-centric view, rather than application-centric view.

-RightScripts require understanding of scripting language.

Bottom line: Where some of the other tools abstract the underlying structures of a cloud-based application, RightScripts require you to develop at the level of those structures directly. This produces some significant starting friction. Nevertheless, once mastered, RightScripts are phenomenally flexible and powerful.

Rick Grehan is contributing editor of the InfoWorld Test Center.

This story, "Cloud control systems tame the ether" was originally published by InfoWorld.

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Copyright © 2009 IDG Communications, Inc.

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