The INTERNET, December 18, 2008 - In what is certainly a blinding epiphany for some it was suddenly realized today that some applications are not well suited for deployment in a public cloud computing environment.

With all the hype surrounding cloud computing these days it is easy to forget that there's more to enterprise applications than just some code and a database. It is a rare application that is an island in the data center, and the more integrated with other systems a given application is the less likely it is that the application will be well suited for deployment in the cloud.


While there are a growing number of solutions designed to address the cloud integration problem (CloudDB, 10Gen, Informatica) the fact remains that applications requiring integration with back office applications are more difficult to deploy in the cloud than non-integrated, stand-alone applications.

"I'm disappointed that my ERP won't be running in the cloud," said one project manager who wished to remain anonymous. "We were going to shut down the mainframe and free the sacrificial chickens for Christmas but then we figured out that the ERP system needed to be integrated with, well, everything and we couldn't ensure security or stability of the integration 'in the cloud' so the chickens will have to stay right where they are." 


There are many use-cases for leveraging the public cloud, but when considering the potential use of the cloud for critical enterprise-class applications it is increasingly important to look at all the factors, especially integration needs, before jumping in with both feet.

The dynamic nature of a virtualized cloud computing environment is certain to make integration a difficult task, especially if the integration is into the application running in the cloud and not out of the application. Data center hosted applications that need to communicate with cloud computing hosted applications may discover that integrating with an application that changes its location on a regular basis makes integrate even more difficult. 

Reliability of the Internet, while generally high, is also a factor to consider. If an outage occurs at any point in the path - and it will  - how does it affect the application? Is the integration capable of store-and-forward behavior or is does it assume that the target application is always available? What changes in business process execution must occur to deal with latency and outages? There are many factors to consider, with integration one of the more critical aspects of an application that needs to be evaluated before pushing an application out into the cloud.

Compliance issues remain, as well. Many applications - especially those storing sensitive and personal information - are subject to myriad compliance regulations like SOX, HIPAA, and PCI. The cloud is not ready to deal with such issues (and neither are those overseeing such regulations) and as such applications falling under these regulations are best left right where they are - in the local data center.

The cloud is a great resource; it's a great new opportunity for leveraging external compute resources on an on-demand basis, but it's not the right deployment model for every application. Yet.

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