Cloud Computing

Advantages of Cloud Computing

[Page 105]The key advantages of cloud computing are summarized as follows:

• Dynamic provisioning/de-provisioning: Clouds provide dynamic, on-demand provisioning of resources. They create a virtual machine (VM) instance whenever end users need it and terminate it whenever they do not.
• Elasticity: Elasticity allows dynamic scaling—that is, provisioning and de-provisioning of computing resources based on actual demand. Elasticity in cloud infrastructure enables the hypervisor to create VMs or containers with the resources to meet real-time demand. The hypervisor is also known as a VM monitor, which is a thin layer of software that creates and runs multiple VMs as well as manages the operation of a virtualized environment on the top of a real host node. Some popular hypervisors include Xen, Kernel-based VM, Quick Emulator, and Oracle VM VirtualBox.
• Scalability: Scalability is a desirable property of any system, network, or process that indicates either its ability to handle an increased workload or its potential to be enlarged in order to accommodate that growth. There are two types of scalability: (1) vertical scalability and (2) horizontal scalability. Vertical scalability (scaling up) is accomplished by adding more resources (e.g., more memory or additional central processing units, or moving an application to a bigger VM) to a single node in a system. Horizontal scalability (scaling out), on the other hand, is the ability to increase capacity by adding multiple nodes (VMs) to a system and dividing the workload among them.
• Multitenancy: Multitenancy is the ability to share resources and costs to support a variety of applications and many end users.
• Pay per use: Cloud computing offers a pay-per-use billing model, by which it reduces the cost and complexity of owning computing and network infrastructures.
• [Page 106]Ease of integration: In cloud computing environments, multiple services from different third parties can be integrated easily. In addition, open application programming interfaces allow telecommunications operators to create the services needed to compete with content and application providers such as Dropbox, Apple, Facebook, Google, and Netflix since the service provider delivers one or multiple services (e.g., cloud services, communications, media content, social networks) over the Internet. Besides the aforementioned advantages, cloud computing poses many challenges, including large and variable wide area network (WAN) latency, real-time response, reliability and high availability, privacy and security, and regulation and compliance, among others.

Evolution of Cloud Computing

The overarching concept of cloud computing is rooted in the 1960s. Cloud computing implements utility computing, an idea discussed by John McCarthy (known as the father of artificial intelligence) in 1961. In utility computing, computing is viewed as a public utility just like the telephone system. Each customer needs to pay only for the capacity that he or she uses.

...