Private clouds: The main attributes
While companies consider blurred security boundaries as a major concern in public clouds, a private cloud applies many of a public cloud's "good attributes" to services that run within a trusted security boundary (that is, on-premise infrastructure or hosted with a trusted third party).
My definition of private clouds applies the following public cloud attributes to an internal business and operational IT model:
- quick provisioning and de-provisioning;
- operation expenditures versus capital expenditures; and
- service management and monitoring.
Virtualization is a key enabler for such on-demand, flexible infrastructure. In a physical environment, scaling this architecture quickly becomes inflexible and cost-prohibitive.
By contrast, virtual provisioning allows you from the outset to overcommit traditionally single-tenanted physical resources, such as CPU, memory and storage, by abstracting the underlying physical infrastructure and making change invisible. This abstraction also allows the physical infrastructure to be scaled up or down as load changes rather than provisioned in advance based on projected load demands.
VMware's private cloud offerings
VMware technologies enable private cloud deployment without some key tradeoffs inherent in public clouds today, particularly security issues. VMware has made significant strategic investment in its product line to take the company beyond commoditized virtualization. In this market, slick management and automation will become the key differentiators, along with mature operational toolsets and processes. Here are some of the key VMware technologies that enable a private cloud model:
- VMware vCenter provides virtual machine (VM) management, administration and patching;
- VMware vCenter Orchestrator offers workflow automation;
- VMware vCenter AppSpeed supplies service-level agreement and application-level response monitoring;
- VMware vCenter CapacityIQ provides capacity management;
- VMware vCenter Chargeback offers a usage-based billing engine; and
- VMware vCenter Lifecycle Manager supplies the provisioning and inventorying of virtual machines.
VMware's technologies thus enable users to create a sharable pool of on-demand computing resources that scale up or down based on workload. These resources can be centralized but also shared among company departments, which then pay back a centralized unit for the capacity they use.
While VMware is hard-pressed to compete in the public cloud space given fierce competition from open source alternatives such as Xen and KVM, private clouds present a more lucrative and ready market for the company. VMware's credentials in the server virtualization market make private clouds a reality for user now.
Private clouds: Shifting in business operations
In September, VMware is expected to release vCloud Service Director (or Project Redwood), a set of tools to tie VMware-based private clouds to external service providers. As VMware moves toward the Redwood architecture, VMware's offerings will be merged into a consolidated automation tool. But in the meantime, users can create an internal cloud computing architecture.
In public clouds, providers multi-tenant their infrastructure. Many customers thus share the underlying network, storage, compute and management infrastructure: infrastructure for Fred's Farmers Bank operates right alongside infrastructure for Joe's Bagels.
A private cloud works similarly. In this shared-services model, a company's business units rent services from a pool of network, storage and compute resources rather than buy and host dedicated infrastructure, the model can drive lower cost and greater agility.
Thus, with a private cloud, your finance department's systems could run adjacent to your catering systems. This model may be an acceptable middle ground for those companies that fear the security implications of placing resources in a public cloud: You get the benefits of "the cloud" with a trusted set of services entirely within your control and regulatory reach.
But the story doesn't end there. Cloud is not about technology; it's about an internal business model shift from a purchasing model (CAPEX) to a rental one (OPEX) in which a central function procures, manages and capacity-plans infrastructure for the entire business. This central function then charges each business unit a fee for capacity use.
Private clouds offer a potentially lower-cost, flexible way for companies to do business . The security concerns inherent in public clouds have discouraged many enterprises from considering a cloud architecture whatsoever. But using a virtualized architecture to create a private cloud architecture is more than possible today -- and carries far fewer risks.
ABOUT THE AUTHOR: Simon Gallagher is a virtualization and cloud computing specialist based in the United Kingdom. He is currently a senior technical architect at ioko, and manages a virtualization- and cloud computing-related blog at vinf.net. He is a MCSE, MCSA, MCTS, MCITP:EA, VCP for VMware Infrastructure 3 and vSphere 4, VMware Enterprise Administrator and has been designated as a VMware vExpert for 2009 and 2010.
This was first published in August 2010