Clouds make it all seem so easy-a tool that is simple to learn and powerful. As always, the devil is in the details, and some missteps in a cloud can brew the perfect storm. As companies pose this question, it seems timely to share some thoughts and recommendations.
We all know that the cloud is simply a chunk of resources, both server and storage, that can be allocated to specific users on an as-needed basis. The resources are priced by both their size or capacity and the amount of time they are used. Virtualization technology has enabled the packaging of workloads in nice little Virtual Machine Disk Format (VMDK) or Virtual Hard Disk (VHD) files which, due to their portability, can be copied, turned on, suspended and removed with relative ease. Thus, the cloud is a perfect place to toss an overflow workload to run for days or weeks or, if the cloud vendors have their way, forever.
But then, if we scratch our heads for a minute, we realize that the cloud is just a very large resource pool, like a mega-cluster. Every IT shop that has adopted virtualization today has a cluster or two (or 10) running virtual machines for a whole host of business customers. Those VMs have associated storage and network resources, and at provisioning time, each VM is assigned its own chunk-just like an external cloud. With one exception: when it is an external cloud, it isn't your problem.
External clouds live out there in the ether, like a power station down the street, or the wind farm on the hill. You don't have to worry if your brand-new plasma TV is sucking down three times the power-the power station keeps on piping you the electrons. And when the power does go out? Sure, you light some candles, but none of us go climbing poles and driving cherry pickers to fix it-it's the power company's problem. And when you move out of your apartment to a new place down the street, and someone has to disconnect your account and reconnect the other account and bill some landlord for the period in between tenants-that, too, is not your problem.