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Summary: The tendency of cloud providers to keep the internal details of their infrastructure secret could cause problems that could wreak havoc in the cloud, a researcher has warned.

Microsofts general manager for Windows Azure, Bill Hilf, thinks it is okay for cloud providers to hang onto the secrets of their internal infrastructure, and says if customers are designing applications that live or die on the basis of very specific requirements, they should not be going to the cloud in the first place.

Youve picked a hammer instead of a screwdriver for a screw, Hilf says. He stresses that less than one percent of the Windows Azure customers he talks to have requirements that go this far, and they tend to be from the government.

Hilf was reacting to a paper published by a Yale academic that argues the secrecy with which cloud providers treat their infrastructure could lead to wide-ranging problems.

In his Icebergs in the Clouds: the Other risks of cloud computing (PDF) academic Bryan Ford argues the lack of disclosure about the inner workings of clouds could put service providers on a collision course with one another.

As diverse, independently developed cloud services share ever more fluidly and aggressively multiplexed hardware resource pools, unpredictable interactions between load balancing and other reactive mechanisms could lead to dynamic instabilities or meltdowns, he writes.

The problems he identifies come in two classes - programming issues and interdependency problems - and look set to become more prevalent over time as cloud providers and services interlace with one another. He presented his paper on Tuesday at the Hotcloud 12 conference in Boston.

A programming issue he identifies is where an application providers load balancer eventually syncs its update cycles with the hardware power optimiser operated by a separate provider. This leads to a death spiral where as power is cut to one server the load balancer moves workloads to another and all incoming traffic ends up oscillating between one server and the other, cutting the systems overall capacity in half - or worse if more than two servers are involved, he writes.

This problem would not arise if cloud providers disclosed the internal technologies they use to scale power, distribute loads and perform other detailed infrastructure management techniques, he argues, as developers would be able to see problems before they arose.

Ford believes the cloud business model encourages providers not to share with each other the details of their resource allocation and optimisation algorithms - crucial parts of their secret sauce - that would be necessary to analyse or ensure the stability of the larger, composite system.

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Cloud secrecy: Will it cause a system meltdown?