If you have worked in IT for long enough, then you probably remember the relentless marketing push from some of the major public cloud providers a few years ago, in which they tried to get customers to move all of their resources to the public cloud. In spite of these marketing efforts, however, it soon became apparent that some workloads are better suited to running on-premises. An organization might, for instance, have privacy or regulatory concerns regarding a particular application and its data, or it might simply cost less to run the application on-premises.
In spite of the fact that some workloads need to remain on-premises, it is difficult to deny the appeal of the public cloud. Cloud providers such as Amazon® and Microsoft® eliminate the up-front infrastructure acquisition costs that would normally be associated with deploying a new workload. Furthermore, cloud providers offer an unprecedented degree of workload flexibility and scalability.
Needless to say, there was a desire among IT professionals to realize these same benefits for workloads that were running on-premises. This led some organizations to develop private clouds, which are essentially privately owned, scaled-down versions of the public cloud infrastructure (or at least something that loosely resembles it).
Hybrid clouds came about because of the management problems that so often occurred in private cloud environments. Even if an organization ran most of its workloads in a private cloud, it was still likely to have workloads running in the public cloud too. Hybrid clouds sought to provide a consistent management experience for both public and private resources—and to make it easier to establish connectivity between these resources.
If you have ever used a public cloud environment, such as AWS® or Azure®, you know the provider allows subscribers to use a web interface to create virtual machine instances and other resources. Hybrid clouds offer the same capabilities. In doing so, however, corporate IT takes on the role of a cloud provider, and the organization’s various workgroups act as tenants. In essence, each section acts as a sort of mini IT department.
Of course, most people do not have the skills of a trained IT professional—the organization’s IT department has to put some controls in place to make it easier for tenants to create resources and to do so in a secure manner. Each hybrid cloud solution works a little bit differently, but in most cases, the IT department creates a series of templates and service catalogs.
Templates control the deployment of resources. A virtual machine template, for example, might automate the creation of a virtual machine. The template would control the hardware resources that are allocated to the virtual machine, as well as the virtual machine’s OS configuration. The template may also include a preconfigured application.
The service catalog consists of a list of resources the IT department has made available to each tenant. A tenant can choose virtual machines and other resources from the service catalog and deploy those resources with only a few clicks. Because the resources have been generated from a preconfigured template via the organization’s IT department, they are guaranteed to be configured in a way that adheres to the organization’s various policies.
One thing that makes a hybrid cloud different from a private cloud is that workloads may be placed on-premises or on a public cloud, and if necessary, can be migrated between the two. In fact, it is common for on-premises resources to use public cloud resources for scalability purposes. For instance, an application server might use public cloud resources to temporarily scale to accommodate a demand spike.
In short, a hybrid cloud offers the ultimate in flexibility and scalability. The architecture keeps the IT department firmly in control while giving authorized users the ability to deploy preconfigured resources without requiring IT department intervention.
Brien Posey is a 13-time Microsoft MVP with over two decades of IT experience. Prior to going freelance, Posey was a CIO for a national chain of hospitals and healthcare facilities and has served as a network engineer for the United States Department of Defense at Fort Knox. Posey has also worked as a network administrator for some of the largest insurance companies in America.
You can follow Brien on Twitter® at @BrienPosey
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