Virtualization And Cloud Computing - IT Organizational Super Powers

The changing paradigm of business agility, digital enablement and the ever evolving needs customer, balanced against the challenges of traditional techniques of IT provisioning and management has historically lead to significant delays and escalating expenditure, which greatly reduced the ability of organization to exploit changing market conditions in order to create business value. In an attempt to improve operational performance, increase security and transparency, and to reduce capital and ongoing maintenance cost, organizations have looked towards virtualization software and techniques in order to facilitate agility and flexibility (Uhlig, et al., 2005).

What Is Virtualization?

Virtualization can be described as the process of configuring, provisioning and management of software-based representations of objects such as Server Hardware, Networks, Storage, Memory and CPU, Desktop Computers and Application Software, to name a few, and has expanded to cover many of the facets of IT provisioning in an attempt to improve the ability to quickly provide access to resource in a reliable, secure and cost effective manner (Perez, et al., 2008).

(educba, 2020)

On the other hand, Cloud infrastructure includes a combination of physical hardware, virtualized components and containerized applications that is deployed to abstract the use of a grouped of shared pooled resources that is managed across physically distributed data centers. While cloud is an environment, virtualization is a technology that enables the shared usage of resources.

Virtualization offers organizations the benefit of using specialized technology capabilities without having to invest in the specialized hardware, effectively managing resources and enabling better productivity through accessibility and reduced risk to the organization in the form of more reliable infrastructure and data storage.

The oldest and most frequent use of virtualization is to create virtual desktops or servers that are isolated from each other, running their own version of an operating system with their own distinct application space. These virtual desktops and servers are typically called Virtual Machines (VM).

How To Virtualize Servers?

Virtualization of servers are made possible by hypervisor technology and software. It forms a layer of abstraction between the hosting server and the guest servers running within the host (Bressoud & Schneider, 1996). Hypervisors are used to emulate the host resources so that the guest machines can use them as if it was their dedicated resources, independent of the operating system used by the guest system. The hypervisor serves as the virtualization layer for storage, memory, processing and networking. The hypervisor is what enables the host to maximize the effective use of server resources, monitoring of guest platforms, reliability and redundancy of guest servers and the flexibility of provisioning images and resources on demand.

Types of Hypervisor Configurations

Two types of hypervisor configuration exist namely Bare-Metal (Type 1) or Hosted (Type 2). Type 2 hypervisors can form part of the operating system (such as the Hyper-V on Windows) which allows desktop users to host multiple Virtual Machines on their computer. Type 1 is more often used by organizational IT departments as this requires technical knowledge and skills to ensure the server boots through the hypervisor technology (Pousa & Rufino, 2017).

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Bare-Metal Hypervisors (Type 1)

Type 1 hypervisors run directly on top of the physical hardware of the host server which means that there is no underlying operating system between the hypervisor and he hardware. Based on this the bare-metal hypervisor has significant performance and increased stability over the hosted model as there is no interaction of interpretation of instructions. The hypervisor is responsible for the typical operating system functions and security as well as the management and operations of the guest virtual machines.

(Bligh, 2014)

Benefits and Challenges of Bare-Metal Hypervisors include

• Better performance due to the direct access to the hardware
• Lower resource consumption by host as it does not have to cater for operating system requirements
• Better security because it is not reliant on security problems of the underlying operating system
• More complex installation and maintenance of the platform as it runs as boot setup
• Sometimes requires additional maintenance and monitoring server if the software cannot be hosted on top of the virtualization host

Hosted Hypervisors (Type 2)

Hosted Hypervisors run on top of the host either embedded within the host operating system or within a separate platform that is run within the host operating system. This option is less scalable as it runs on top of the operating system and is reliant on its scalability capabilities. Because it typically runs as just another application on the host, it is constrained by these parameters which reduces performance because of the multiple layers and translation that instruction must traverse.

(Bligh, 2014)

Benefits and Challenges of Hosted Hypervisors include

• The management of hosted hypervisors are typically a lot simpler as it is either built into the host operating system and support standard user interfaces and setup and maintenance process or can be installed as an application which adheres to the operating system interfaces
• Because of its lower cost of implementation, it is suitable for test or sandbox environments that can be provisioned and torn down quickly
• Users can provision and manage their own instances as the application is hosted on their desktops or laptops
• Smaller hosts can degrade in performance depending on resource constraints and consumption from host and guest
• Reliant on the host operating system security to ensure that the environment is kept secure
• Does not include the full set of features and capabilities of hosted hypervisors in terms of reliability, scalability, resource constraints and management

Cloud Hosting Models

 Other models of cloud hosting and virtualization include IaaS (Infrastructure as a Service), CaaS (Container as a Service), PaaS (Platform as a Service), FaaS (Function as a Service) and SaaS (Software as a Service). IaaS is very much in line with server virtualization in that it offers infrastructure servers on demand with the customer specifying guest operating system, applications and maintenance. CaaS provides container hosting and management as a service backed by cloud based scalability and reliability, with users responsible for managing container images, constructing clusters and groups, and load balancing and fail over, which can be managed through a hosted service such as Kubernetes. PaaS offers organizations the ability to deploy bespoke software applications to hosting platforms such as RDBMS and Webservers without having to consider the underlying resources. FaaS represents units of work, which is pieces of code written to perform a specific function, and is launched, executed and hosted on managed servers which offers reliability and scalability, where users are only concerned with the function intention. SaaS offers the highest level of virtualization with users only concerned about the application, not considering any of the management and resources required to host it.

(Digital Cloud Training, 2020)

To illustrate this in everyday terms, below is an illustration of the various options using Pizza-as-a-Service.

(Kerrison, 2017)

References

Bligh, A., 2014. What Does a Hypervisor Do?. [Online] Available at: https://www.flexiant.com/2014/02/05/what-does-a-hypervisor-do/ [Accessed 29 Mar 2020].

Bressoud, T. C. & Schneider, F. B., 1996. Hypervisor-based fault tolerance. ACM Transactions on Computer Systems, 14(1), pp. 80-107.

Digital Cloud Training, 2020. CLOUD COMPUTING SERVICE MODELS – IAAS, PAAS, SAAS. [Online] Available at: https://digitalcloud.training/2019/10/27/cloud-computing-service-models-iaas-paas-saas/ [Accessed 29 Mar 2020].

educba, 2020. What is Virtualization?. [Online] Available at: https://www.educba.com/what-is-virtualization/ [Accessed 29 Mar 2020].

Kerrison, P., 2017. Pizza as a Service 2.0. [Online] Available at: https://medium.com/@pkerrison/pizza-as-a-service-2-0-5085cd4c365e [Accessed 29 Mar 2020].

Perez, R., van Doorn, L. & Sailer, R., 2008. Virtualization and Hardware-Based Security. IEEE Security & Privacy, 6(5), pp. 24-31.

Pousa, D. & Rufino, J., 2017. EVALUATION OF TYPE-1 HYPERVISORS ON DESKTOP-CLASS VIRTUALIZATION HOSTS. IADIS International Journal on Computer Science & Information Systems., 12(2), pp. 86-101.

Taylor, C., 2108. Guide to Hypervisors. [Online] Available at: https://www.serverwatch.com/server-trends/guide-to-hypervisors.html [Accessed 29 Mar 2020].

Uhlig, R. et al., 2005. Intel virtualization technology. Computer, 38(5), pp. 48-56.