A hybrid cloud combines public and private cloud functionality, enabling an organization to enjoy the best of both architectures. There are a variety of scenarios in which an organization might prefer to implement a hybrid cloud architecture.
If an organization has existing services implemented on its own physical hardware, it might want to maintain those services while adding others from a public cloud provider. For example, the organization might have reached the physical capacity of its own datacenter and does not want to invest in a major facility expansion.
An organization might also use public cloud resources to extend the capacity of its private cloud or its in-house network during temporary periods of greater need, such as seasonal business increases.
This technique, called cloudbursting, eliminates the need for the organization to pay for hardware and other resources that are only required for brief periods. Because it is possible to connect the public and private services, the resources can interact in any necessary way.
For example, a business with an e-commerce website implemented in a private cloud can add public cloud-based servers to its web server farm to accommodate the increase in traffic during its busy holiday season.
Another possibility is that an organization might be subject to the type of data storage or other security requirements described in the previous section, but they do not want to build out their entire infrastructure in a private cloud.
In this scenario, the organization could conceivably deploy a database containing the sensitive data in a private cloud and use a public cloud provider for a website implementation linked to the database.
This way, the network can comply with the storage requirements without having to go to the expense of deploying web servers and other services in the private cloud.
The same is true for a variety of other services; organizations can keep their sensitive data and services in the private cloud and use the public cloud for the nonsensitive services.
Organizations can also use private cloud resources to run legacy equipment or applications, while all the other services run on a less expensive public cloud.
Some cloud providers supply tools that enable administrators to manage their public and private cloud resources through a single interface. Microsoft Azure provides Azure Active Directory, for example, which enables a subscriber to use the same directory service for public and private cloud resources allowing administrators to access both with a single sign-on. Azure also provides management and security interfaces with built-in support for hybrid cloud architectures.
Exam Tip
The MS-900 exam requires you to understand the role of the public, private, and hybrid architectures and the IaaS, PaaS, and SaaS service models in cloud computing. However, be sure also to understand how these elements fit in with the Microsoft 365 product.