Why a Hybrid Cloud is not a mix of on-premise and Cloud
When browsing through SAP sites, like sap.com, or SAP Community Network, you might find various definitions of the term “hybrid cloud,” some of which are very accurate. Others, however, seem to be created in a situational purpose or context. While in general it is legitimate to devise and use purpose-built definitions, this process might create confusion in such an innovative context as cloud computing. Since SAP is gaining serious momentum in the cloud, it is more important than ever that we adhere to commonly accepted terms and definitions; otherwise, we will adversely affect the velocity of our adoption of innovations and our ability to comprehensively sell our solutions.
The cloud computing definition by the NIST (National Institute of Standards and Technology) is widely accepted as the common standard. It divides cloud computing into five essential characteristics, three service models, and four cloud deployment models, three of which are highlighted in this blog post:
- Private cloud: […] “exclusive use by a single organization” […]
- Public cloud: […] “open use by the general public” […]
- Hybrid cloud: […] “distinct cloud infrastructures that remain unique entities, but are bound together” […]
The NIST explicitly uses the term “cloud infrastructure” to define the hybrid cloud. This connotes that a hybrid cloud is the sole combination of clouds. A most prominent example is the combination of a private cloud and a public cloud. It also means that there is no ambiguity: the mere combination of cloud and on-premise should not be called a hybrid cloud. The importance of this differentiation immediately becomes apparent when assessing the implications either definition has on the IT operation. Following the NIST definition, a hybrid cloud not only implies a connection between “distinct cloud infrastructures,” it also enables “data and application portability,” by utilizing standardization or proprietary integration technology of the interconnected clouds.
In contrast, the combination of on-premise and cloud software does not come with any standardization or even automation, and thus does not comply with the essential cloud computing characteristics: on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service.
If a company has even a single SaaS application, it is most probably being connected to some legacy on-premise application. A hybrid cloud demands that these on-premise applications, for example an SAP ERP System, will be transformed into a private cloud environment first, for example migrated to SAP HANA Enterprise Cloud, and then connected to a public cloud.
For that reason, the combination of on-premise and cloud is referred to as “integrated”: Depending on the deployment it could be a landscape, an approach, a scenario, or a mixed environment; whereas, only the combination of clouds, enabling data and application portability and fulfilling the essential cloud computing characteristics, should be called a hybrid cloud.
We need to keep this in mind when talking about such deployment options, so everyone is clear about what to expect.