Adequate monitoring tools and policies are also needed to guarantee service availability and performance, and meet regulatory demands. Key vendors in this area include IBM, VMware, Neustar and AccelOps, according to Poon.
Enterprises also need to tackle the corporate culture in order to effectively deploy an internal cloud. Users often resist changes to the status quo, but that does not mean IT should avoid innovation.
"When a company decides to build an internal cloud to share a pool of computing resources for the deployment of user-specific applications, it should provide users with a familiar interface for accessing resources so that little or no training is required to simplify the transition," the Yankee Group report states.
While numerous vendors have tackled one or more aspects of the cloud-building process, several say their platforms alone are robust enough to build a private cloud. VMware has dubbed the latest release of its virtualization software a "cloud operating system," while cloud building software packages are also available from Platform Computing, 3tera, Eucalytpus Systems and other vendors.
VMware's vSphere isn't a complete cloud platform yet, lacking self-service deployment, automated provisioning and billing, but VMware can be expected to bolster these aspects in the future, Staten says.
Platform Computing's ISF software aggregates servers, storage, networking tools and hypervisors to create a shared pool of physical and virtual resources. It is perhaps the most comprehensive cloud building software, according to Staten, noting that it includes a workload distribution engine; an infrastructure aggregation layer; a self-service portal for IT administrators; metering and monitoring; and robust APIs for integration with third-party tools.
SAS, a business intelligence software vendor, is piloting Platform ISF internally to create a self-service portal for developers allowing them to "quickly and reliably provision and deploy compute and application resources," says Cheryl Doninger, research and development director for the enterprise computing infrastructure at SAS.
Pooling together server, storage and networking resources will eliminate inefficiencies in SAS's previous method of deploying custom computing setups to individual R&D groups.
SAS went with Platform ISF because the company needs to support multiple hypervisors and wanted its cloud to include both physical and virtual servers, possibilities not supported by VMware's vSphere. "Even though virtualization technology is getting better, there is still a performance consideration when you move an application from a physical deployment to a virtual deployment," Doninger says.
Eucalyptus Systems, an open source company, provides a Linux-based platform that installs on existing hardware and is designed to let an internal data center operate like the Amazon Elastic Compute Cloud, says Eucalyptus CTO and co-founder Rich Wolski. Virtualization alone does not give users control over their own resources, Wolski explains, so products like Eucalyptus enable the self-service interface and sharing of resources.
"Users can configure their particular piece of the cloud in exactly the way they want, just like they do with Amazon," Wolski says. "The cloud enables the user to have a great deal more control over the piece of infrastructure they are entitled to use. Without a cloud, the administrator has to control everything."
Private cloud adoption may be low today, but the market is expected to heat up significantly over the next few years. In addition to software-only products such as Platform ISF and Eucalyptus, companies such as IBM and HP are selling hardware/software bundles that work in similar ways, albeit without the benefit of reusing existing hardware.
The analyst firm Gartner predicts that IT organizations will invest more in private cloud services than in external cloud providers through 2012.
"Private cloud services will be a stepping-stone to future public cloud services," Gartner says. "For many large organizations, private cloud services will continue to be required for many years, as public cloud offerings mature."