In the early days of the cloud, the public cloud was the cloud. The cloud was generally understood to be a platform created by a provider who offered multi-tenancy infrastructure as a service. As time went by, we saw cloud providers bring many different cloud service modalities (PaaS, DaaS, etc) and deployment methodologies (private cloud, bare metal cloud) to market.
As often happens, industry commentators who like to drum up controversy made much of the advantages of one type of cloud compared to the other, particularly the relative advantages of public and private clouds. In reality, both have their place, and as the market has matured, it seems that the hybrid cloud, which mixes public and private components, will be the deployment scenario that most established businesses — as opposed to startups — adopt.
Established companies with existing IT infrastructure and commitments often have neither the desire nor the ability to migrate lock, stock, and barrel into the public cloud. There are a variety of reasons – some valid, some spurious.
- Security – For the most part, the narrative that private clouds are inevitably more secure than public cloud platforms is an expensive canard. The expertise to build secure cloud platforms resides with public cloud vendors and very rarely with the IT departments of other companies. But there are legitimate reasons why a business would want to keep some of its data in-house. A hybrid cloud platform would offer them the best of both worlds.
- Legacy systems – Many companies have extensive business critical IT infrastructure that cannot simply be abandoned. Hybrid clouds can be used to bring some of the benefits of cloud computing to businesses that rely on legacy infrastructure. Banking is a classic example of this scenario: many legacy banking IT platforms are built around a batch processing model that does not meet the real time needs of customers. A hybrid cloud allows banks to wrap real time systems around their existing batch processing systems.
- Redundancy – Public cloud-based redundancy for private infrastructure is a less expensive, more flexible method of creating resilient networks.
- Mixed Environments — Some applications are better dealt with on private infrastructure because of a need for extremely low latencies or a desire to avoid having to push workloads through the public Internet. Most organizations that require very low latency systems don't require them for every workload, so a mixed environment allows them to benefit from the flexibility of public clouds when they offer the best solution.
There is very rarely a solution that solves all possible problems. The public cloud comes near it, but there are scenarios in which private infrastructure deployments are still optimal. Hybrid clouds allow businesses to leverage the specific benefits of each, and they are likely to be the IT deployment strategy of choice for most established companies migrating to the cloud.