In a hybrid environment, a private cloud can reach beyond the firewall to grab resources from the provider when there is a spike in need. It is early, though, and definitions of cloud computing architecture remain fluid.
Still, one trend is certain: Cloud computing is a growing reality, and many have begun to venture into it via private cloud initiatives.
"We see the uptake in the private cloud situation on a pretty steep curve," said John Andrews, the CEO of Evans Data Corp, a technology research firm. "No. 1, it's the maturity of the industry. There are many more and larger players entering into it."
'Hybrid' cloud adoption
In its "Cloud Development Survey 2009," Evans found that over the next 12 months, 48.9% of developers expect to deploy applications into a private cloud. Of the 500 developers from system integrators, value-added resellers and independent software vendors surveyed, 29.7% were working on applications destined for a private cloud environment.
Amazon shaped the cloud space early on, but it is a nontraditional vendor. Andrews said now that more traditional players such as Microsoft, IBM and even Oracle Corp. take cloud computing seriously, enterprises recognize it as a coming reality.
Users of Amazon's public cloud Elastic Compute Cloud (EC2) offerings reported using it mostly for experimentation, prototyping and noncritical applications.
The Evans Corp. survey also found that the first applications deploying in public clouds focus on testing and development, enterprise resource planning, customer relationship management and communications. But developers are looking at private clouds for more mission-critical e-commerce applications.
Evans has seen an increase in interest in hybrid cloud initiatives, involving both public and private clouds. Theresa Lanowitz, an analyst and founder of voke media LLC, said she's come to similar findings.
"What we're seeing is that people are initially going to go to a hybrid," Lanowitz said. "There are really two driving forces. There's the economic force that's saying business are really being driven to lower their capital costs. And then you have the technological force. The cloud is really being enabled by the fact that virtualization is mainstream and actually works."
Overcoming cloud hurdles, hype
But even with cloud adoption gaining traction, numerous hurdles remain. The single greatest concern with public cloud computing remains security. Lanowitz said early on, cloud providers focused on graphical user interface and usability. Cloud-based virtual lab provider Skytap Inc., for example, has a resource dashboard where you can literally activate a machine with a button and select the operating system from a drop-down menu.
Igor Moochnick, the founder and VP of engineering at IgorShare Consulting, said it will be a while before enterprises trust public cloud providers enough to host their mission-critical applications. Over the past year, both Amazon EC2 and the Google App Engine have experienced periods of downtime. In the meanwhile, he said the hybrid cloud approach will likely become quite popular -- especially with large enterprises.
"The private or hybrid cloud becomes very attractive to big companies because they have already invested in this hardware," said Moochnick. "They already have these mission-critical processes that they can't afford to lose."
With all the hype and so many vendors packaging their offerings as cloud products, it is important to stay abreast of just what it means to be working in a "cloud" system.
"You're finding that people are claiming what they're doing is on a grid of machines or on cloud," said Mark Hodapp, a principal consultant at Cloud Savvy. "Or are they really referring to the fact that they're deploying to a virtual environment. In my experience, a lot of people refer to their internal operations, as it is today, as a cloud machine."
For developers, Hodapp said a combination of Amazon EC2 with RightScale cloud management is the most successful and mature option. Next in line, he said,are Google App Engine and Microsoft Azure. These technologies have come along quickly but still have several issues to work through.
Rob Barry is a news writer for SearchCloudComputing.com and SearchSOA.com.