Cloud's ability to ratchet server power and storage up and down as needed suits the demands of online marketing campaigns that tend to gear up and wind down quickly. So a few years ago, sneaker manufacturer Puma ran fast toward adoption.

But soon the $3.6 billion sportswear company found itself dealing with four different cloud providers, each with its own contract terms, pricing and technology options. Puma decided to try to get control of that "large, wild infrastructure" by consolidating clouds, says Jay Basnight, the company's head of digital strategy.

That cloud consolidation projects are starting to emerge shows how entrenched cloud computing has become in the IT landscape, says Chris Harding, director of interoperability at The Open Group, a global consortium that leads the development of open, vendor-neutral IT standards and certifications. The problem is that switching clouds isn't as simple as the cloud hype suggests, he says. Applications built for one vendor's cloud may not run well on another's. CIOs have to pay attention to different programming interfaces and architectures.

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