The primary mission of computing has always been to automate business. The secondary mission has been to automate the automation, a quest that grows ever more urgent as data center technology achieves such towering complexity it threatens to collapse under its own weight.
The private cloud is the latest attempt to boost the efficiency and agility of the vast assortment of hardware and software sprawled across data centers. The idea is to pool compute, storage, and network resources and manage them from a central software control point rather than scrambling to provision, monitor, manage, and reconfigure all that infrastructure manually.
Predictably, the organizations with the most experience designing and running shared infrastructure are the public cloud service providers themselves. Amazon, Google, Microsoft, and Salesforce can't manage their data centers the old-fashioned way -- with static chunks of infrastructure dedicated to individual application instances -- and hope to deliver services to millions of subscribers over the Internet reliably and cost-effectively. These pioneers' experiences running public clouds at scale have yielded the basic models for the private cloud.