of properties that must to be kept in mind [4]:
1 a. Multiple devices need to be connected via LAN, WAN, or VPN with a common middleware that provides an API for user services. Rather than using a vast network of API, a single operating system must be used throughout the network and APIs can be built on top of that.
2 b. Resources are made available to all the connected devices via virtualization and it can be scaled up to any limit.
3 c. The middleware does all the coordination between devices and resources are made available on demand basis with proper authentication.
1.2.2 Why Hybrid Cloud is Required?
Hybrid cloud means different service to different people [5]. Need of an organization depends on diverse aspects of IT. As the perspective of application designer, business developer, and infrastructure support personnel is different from one another, their expectation from the system also varies.
Figure 1.1 General architecture of hybrid cloud.
Application programmer always requires support for edge technologies. Availability of high-end resources and cutting edge technology support is the primary concern of a developer. Off premise support for such is essential. Flexibility in deployment of changing technology services, speedy availability of the new resources required by the solution, peak support for on-premise system, and seamless and continuous integration of system services are key issues need to be dealt in hybrid cloud. Disaster management is also an integral part of it.
On the contrary, infrastructure support personnel always look for a steady build in support for smooth execution of overall activities of the organization. Off premise support for virtualized computing resources is often necessary in IT. In this scenario, the role of infrastructure support team is very crucial. Visibility of all the resources wherever it is, monitoring them in federated way following SLA, management of deployed setup for auditing and security management, accessibility of all resources, and control provisioning are key consideration in case of hybrid cloud.
Business developer, on the other hand, focuses on consumer marketing in cost-effective manner [6]. The need of IT business has manifolds. Support for newly growing technology like mobile or web-based application requires agile and easy to extend network, and at the same time, consistent system and stable process management services cannot be replaced. So, business developers have to look into all these aspects, and at the same time, they have to focus on the cost. The maintenance and management cost should not exceed the overall financial budget. Looking at the SLAs and software license exposure, they need to design financial plans that can fulfill the whole organization’s prerequisites.
No matter how well we plan the future, it still remains uncertain and hybrid cloud provides the facility to use cloud services as and when it is required. It is also quite unlikely that workload of an organization remains same throughout the whole year. Suppose an organization is working on big data analytics, it can take help of public cloud computing resources for high complex computations but that too is not needed for long run, may be require for few months. Here, public cloud resources can be borrowed for few months only. In the same way, startup companies can start with some trivial private resources and take cloud services for rest of the processing. Then, based on the performance, they can plan to expand the business with the help of public cloud. All these are possible only in case of hybrid cloud as it has agility, scalability, data reliability, speedy recovery, and improved connectivity and security.
1.2.3 Business and Hybrid Cloud
According to Hybrid Cloud Market report, in 2018, hybrid cloud market was USD 44.6 billion and expected to grow to USD 97.6 billion by the end of 2023 with Compound Annual Growth Rate (CAGR) of 17.0% [9]. IaaS is expected to hold a large market in the forecast period as it facilitates to migrate workload from on premise to off premise in high peak hours. Hybrid web hosting also hold a big market as it provides management of all hosting services in just single point of contact. North America was the most promising hybrid cloud market place in 2018 and Asia Pacific areas shows the highest CAGR. So, hybrid cloud is a promising area in business. Major sectors using hybrid cloud computing are healthcare, retail, government, or public sectors, banking, entertainment media, insurance, finance, communication media, etc. [14]. According to a report published by Mordor Intelligence, North America, Middle East, Africa, Europe, and Asia Pacific are top growing regions worldwide. Figure 1.2 shows the hybrid cloud market. Green portions represent highly growing market. Hybrid cloud management software solution is the main reason of this popularity. Starting from deployment to quota management, customization of service library, costing, performance management, and governance, everything is taken care of, like the software management tool. Mostly, the services provided by public providers are restricted to some architecture or technology and vendor specific. But the management tool provided by hybrid providers helps to amalgamate different services provided by various vendors. Amazon and Microsoft, the giants in this field, are working hard in the up gradation of their management software by including advanced infrastructure templates, libraries, API, and apps. In India, IBM is also approaching toward hybrid cloud and AI [15]. IBM invested $1 billion into a cloud ecosystem project in the month of August. They are expected to invest more in the coming time. In India, 17% of organizations are planning to spend investment from 42% to 49% on hybrid cloud by 2023 according to a study by IBM IBV. Since India is heading toward a digital transformation and self-reliant camping, so the opportunity of new technology adaptation also increasing.
Figure 1.2 Market trend of hybrid cloud [14].
1.2.4 Things to Remember When Deploying Hybrid Cloud
Having an understanding what hybrid cloud is and how it facilitates the activities of any organization, now, we need to understand some factors that have to be considered before the deployment of hybrid cloud.
Selection of best suitable platform for cloud: As discussed, the need of every organization is not same. Before deployment of the hybrid cloud, organizations need to have a plan for the services; it will borrow from the public cloud. If it is going to use only SaaS, then it is not a problem but it is going to use IaaS or PaaS and then it is very important to take the correct decision from the commencement of the service as building a hybrid structure that would not be able to handle additional workload generates severe problem.
Whether to use unified OS or not: In true hybrid cloud, a unified OS is installed in the middleware that basically governs the overall functionalities. But in some cases, on-premise system may be operated by its own OS then just with the help of internet they can connect to public cloud. The performance of this architecture will be vast different from unified OS. OpenStack, VMWare cloud, Nutanix, and Kubernetes are some example of cloud OS framework. These frameworks are sufficient building the middleware and it provides OS and all supporting application for the smooth execution of all activities in hybrid cloud.
How to manage different activity: Huge amount of data need to be handled in case of hybrid cloud. A hybrid system should look into smooth accessibility of data, and at the same time, security of data needs to be guaranteed. Anyone cannot host any data onto the public cloud. Proper personnel with adequate experience need to be engaged for the management of dedicated applications.
How security of data will be guaranteed: Since data is moving in between public and private cloud, it needs to be secured. Through security