How to buy cloud computing services

If you need more computing or storage capacity in your data center but capital expense is an issue, then a public cloud computing service makes a nice option. You get on-demand IT resources that are infinitely scalable and you pay for what you use.

But running an enterprise application in a public cloud isn't as simple as some providers might have you believe.

Buying a cloud service isn't just about the nuts and bolts of computing and storage, cautions Dave Powers, associate information consultant at Indianapolis-based Eli Lilly & Co., which has been using Amazon Web Services (AWS) since April 2008. "It's about all of the Web services and capabilities built on top of the cloud that makes being able to spin up some computing, do some storage and then tear it all down very low-friction."

Before committing to a cloud services provider, IT execs should understand exactly what resources they have on hand, what they're buying, and how running on a public, shared server infrastructure will affect applications and business processes.

Tony Bishop, CEO of Adaptivity, a consulting firm specializing in next-generation IT infrastructure, puts it this way: "As much as cloud does away with the limitations of hardwired infrastructure, it doesn't alleviate the need for proper planning and IT integration discipline. It amplifies it."

Here are some practical guidelines on issues to consider and questions to ask when buying cloud services.

1. Are your applications ready?

For Bernard Golden, CEO of HyperStratus, a consulting firm specializing in advanced IT technologies, the top priority is figuring out whether an application needs modifications or a complete re-architecting for use in the cloud. "In some cases, your application architecture could even constrain your cloud options," he says. Golden uses this simplistic case as an example: "Say you have something running on an Alpha chip-based computer. You're not going to find a cloud service that can run Alpha binaries."

Failure to rethink an application might even defeat the purpose of using a cloud service, says Eli Lilly's Powers. This was one of the company's first lessons learned as an AWS user, he adds.

"At first, we literally picked up a workflow from our internal grid environment and dropped it into the cloud. While that worked, we learned that we had constrained ourselves. In the cloud, we had this infinite amount of compute and storage, but our application, designed to run inside Eli Lilly's fixed-size computing environment, couldn't take advantage of it," Powers says.

Now, the Eli Lilly team might chunk up an application and move data into and out of the cloud in smaller, more consumable pieces, or it might store some data in the cloud, so an application doesn't have to retrieve it from the enterprise data center, Powers explains.

And, Powers makes sure every cloud-destined application accounts for fault tolerance. "If you're buying infrastructure as a service, you have to understand that a machine can go down at any time, and your application design needs to consider that," he adds.