On the network front, reliability and security become more important than ever in a cloud environment because of the reliance on a consolidated pool of processing and storage, Poon says. In addition to strict access controls, the network must be robust enough to survive a performance hit that could be caused by virtualisation.
"Running virtual machines on a single server and accessing them via Gigabit Ethernet could overwhelm the network, leading to degraded performance," Poon writes in a report titled "Rebuilding Corporate Data Centers as Private Clouds." "The situation is exacerbated as enterprise users expect to access business applications anywhere, anytime, resulting in applications being dynamically rerouted on the fly to meet specific requests."
In terms of process, automation is key for dynamically scaling IT resources and enabling quick provisioning and deprovisioning of computing instances and applications.
"Automation is a key feature used in the cloud computing environment to orchestrate the interplay between the physical and virtual components required to build an internal cloud," Poon writes. "As the number of virtual machines per physical server continues to swell, it becomes very cumbersome for enterprise IT to manually manage processes such as installing and configuring the OS and doing patching and upgrades for ongoing support."
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 virtualisation 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.
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