As organizational business grows, there is a need to extend the enterprise operation along with the IT infrastructure. In other words, the onsite data center needs to be extended by adding more servers and resources to fulfill business demands. There is also a need to optimize and perform efficient utilization of available resources. High-end servers can't be left underutilized, as this will be a waste of the available resources. Purchasing more and more IT equipment increases the organizational infrastructure costs. Also, large servers tend to occupy more and more space in data centers. This becomes a problem and there is a need for a flexible and scalable model that will allow on-demand infrastructure scale-up and scale-down.
One solution is to use a private cloud that provides on demand scaling up and scaling down of the infrastructure by spinning up virtual machines. A private cloud will certainly solve the problem of flexible scaling and efficient utilization of resources. However, since a private cloud resides within the data center, it still requires large amounts of physical resources, which must be owned by the organization. Despite efficient utilization of resources, if the organization needs more infrastructure, a private cloud doesn't completely solve the problem, as the cost of owning the infrastructure must still be borne by the organization.
So, the other solution is to migrate the entire data center to a public cloud such as AWS or Azure. A public cloud will ensure that we have ample resources that can be scaled up and down based on requirements. Organizations don't have to worry about purchasing large servers and arranging floor space for accommodating them in their private data centers.
However, there are many downsides to using a public cloud. Migrating existing applications to the cloud is complex. There are portability problems as system architectures differ. Also, as the resources are scaled up and the data center expands, the costs can climb significantly. The overall costs of using a public cloud are high. Moreover, there are security concerns. Since organizational data could be confidential, putting it on a public network would not be liked by the IT security teams. Thus, using a public cloud alone doesn't solve the problem either.
Since both public and private cloud models have their pros and cons, there is a need to combine both the models and create a more suitable platform for the organization's needs. A cloud platform that is a combination of private and public clouds, and connected using an encrypted network, is referred to as a hybrid cloud. The National Institute of Standards and Technology (NIST) defines a hybrid cloud as follows: "A hybrid cloud is a combination of public and private clouds connected together using a standardized network link that enables portability of data and applications." It could be a combination of a private cloud inside an organization with one or more public cloud providers, or a private cloud hosted on third-party premises with one or more public cloud providers.
A typical use case of the hybrid cloud model is a combination of customer facing systems (such as mobile phones) and systems of record management. For example, an e-commerce organizations might leverage their data center to manage transactions made by their customers using the frontend that is running on a public cloud. In other words, the frontend running on a public cloud will be connected to the datacenter. An organization might also use a third-party cloud service that verifies the credit of customers who choose to pay using the EMI option. They may also use the public cloud to expand their servers in case of high network traffic during online sales and holiday periods.
The hybrid cloud is thus becoming a widely used cloud model that adapts to rapid changes in technology and business in terms of networking, storage, and computing requirements.