Clouds are typically classified into four different topologies: private, public, community and hybrid clouds. Let's focus on hybrid clouds: what are the use cases that require this topology, what are the challenges, and who stands to benefit from the hybrid cloud trend?

First off, a definition: A hybrid cloud is a topology in which more than one cloud infrastructure is utilized to solve a particular problem. Some examples:

• In order to generate a monthly report of your customers' stock portfolios, you need to process some personal information (e.g., name, address, credit card number) along with non-personal information (e.g., tick data for stocks). Industry regulations prohibit you from loading the personal information as-is to a public cloud such as Amazon. So, you process the non-personal information on Amazon, and the personal information is processed on a private cloud that sits behind your company's firewall.
• Your application needs services that are only available on distinct public clouds. For example, your underlying analytic database is Amazon Redshift, which excels at near real-time analytics, so the data center processing must be run on Amazon. But, you also need the entity extraction and sentiment analysis features of IBM's Watson, which are readily available only on IBM's Bluemix cloud platform. In this case, the application would make use of resources located both in the Amazon public cloud and the IBM public cloud.
• Your company has developed all its applications based on Google App Engine hosted in the Google public cloud, and your engineers love the development environment. You just purchased a company that hosts all its applications on Amazon. The company wants to see consolidated reports across the two distinct businesses. In this case, there probably is no ROI justification for porting either of the cloud applications. Instead, you will let each system continue to process data as before, and use some other tool, e.g., Tableau, to consolidate the results.

As you can see, there are many real-world examples that justify deployment of a hybrid cloud. But be aware of the challenges you will face in deploying and managing a hybrid cloud. In order to successfully execute a single use case (e.g., generate a single report), you need to successfully provision resources on two different cloud infrastructures, run processes on both clouds to success, combine the results, and then decommission all the resources on both clouds. If there is a failure at any stage on any of the clouds, you need to understand the impact of that failure on related processes running on other clouds that are part of the same use case.

The real challenge of hybrid clouds is management: How do you manage the resources of distinct cloud infrastructures as if they were a single fabric? Solving this problem requires a new generation of cloud management tools that goes beyond the management tools provided by any individual cloud vendor.

Another important observation: all the examples given above are relevant to large enterprises rather than to SMBs. That's the real market for hybrid cloud technology - large enterprises that are accustomed to dealing with large software vendors rather than start-ups.

The companies that are best equipped to answer this challenge are large software vendors that have years of experience providing complex management systems to large enterprises, which are the main customers for hybrid clouds. Not surprisingly, the leading vendors of hybrid cloud management tools are familiar names like Microsoft, SAP and IBM - "The Empire," to borrow an image from Star Wars. Many of these companies came later to the game, after "first mover" advantage went to upstarts like Amazon and Rackspace. But the rise of hybrid clouds, and the accompanying management challenges, have given The Empire an opportunity to strike back at the upstarts and carve out their own niche in the cloud ecosystem - management of complex hybrid cloud topologies. This niche, along with cloud launches by giants such as IBM and Microsoft, mean that the battle for dominance in the Cloud between the Empire and the rebels is far from over.