Understanding Implementation Levels of Virtualization in Cloud Computing: An Overview

Summary: Virtualization is a technology that creates virtual versions of physical resources, enabling efficient use of hardware in cloud computing. It allows multiple operating systems to run on a single machine, optimising resource allocation and enhancing flexibility. Understanding virtualization is essential for leveraging cloud computing effectively.

Introduction

Virtualization is the creation of a virtual — rather than actual — version of something, such as an operating system, a server, a storage device or network resources.

In cloud computing, virtualization enables multiple operating systems and applications to run on the same physical hardware. We can achieve this by using a hypervisor. It acts as a bridge between the hardware and the virtual operating systems, allowing for smoother functioning.

For example, we can virtualize a single physical server to host multiple virtual machines (VMs), each running its own operating system and applications, thereby maximizing resource utilization and reducing costs. Virtualization is a core technology in cloud computing, enhancing resource sharing, improving computer performance, and increasing application flexibility.

Key Takeaways

• Virtualization allows multiple operating systems to run on one physical machine.
• It optimises resource utilisation, reducing hardware costs for organisations.
• Key methods include full virtualization, para-virtualization, and OS-level virtualization.
• Virtualization is foundational for effective cloud computing infrastructure.
• Understanding virtualization enhances flexibility and scalability in IT environments.

Key Methods of Virtualization Implementation

Various methods of implementation levels of virtualization in cloud computing  exist, each catering to different needs and offering unique advantages. These methods determine how resources are abstracted and shared. Here are the key methods:

Full Virtualization

This method involves creating a complete simulation of the underlying hardware, allowing multiple operating systems to run unmodified on virtual machines. Each VM operates independently, providing a high level of isolation and security.

Para-Virtualization

Unlike full virtualization, para-virtualization requires modifications to the guest operating systems to enable them to communicate with the hypervisor. This approach enhances performance by reducing overhead but requires more complex setup and management.

OS-Level Virtualization

Also known as containerisation, this method allows multiple isolated user-space instances (containers) to run on a single operating system kernel. It is lightweight and efficient, making it ideal for microservices and applications that require rapid deployment.

Application Virtualization

This approach abstracts applications from the underlying operating system, allowing them to run in a virtual environment without the need of installing it directly on the host machine. It simplifies application management and enhances compatibility across different systems.

Network Virtualization

This method involves creating multiple virtual networks on top of existing physical networks, enabling better resource allocation, enhanced security, and simplified network management.

Storage Virtualization

This technique abstracts physical storage resources into a single logical storage unit, allowing for efficient management and improved data availability across different storage devices.

Implementation Levels of Virtualization in Cloud Computing 

The implementation levels of virtualization in cloud computing involves several layers, each addressing different aspects of resource abstraction. These layers include Instruction Set Architecture (ISA), Hardware Abstraction Layer (HAL), Operating System Level, Library Support Level, and User-Application Level. Understanding these layers is crucial for designing and managing virtualised environments effectively.

Instruction Set Architecture (ISA) Level

ISA virtualization involves emulating the instruction set architecture, allowing legacy codes written for different hardware configurations to run on virtual machines.

The interpreter interprets the source code and then converts it into a readable hardware format. Key examples of ISA virtualization tools include Bochs, Crusoe, and QEMU. ISA virtualization makes the virtual machine hardware-agnostic, providing flexibility in running applications across different hardware platforms.

Hardware Abstraction Layer (HAL)

The next level of virtualization in cloud computing is the Hardware Abstraction Layer (HAL) enables virtualization at the hardware level by utilising a hypervisor. At this level, the virtual machine manages the hardware using the virtualization process. It allows the virtualization of each hardware component, such as the input-output device, the memory, and the processor.

In the cloud-based infrastructure, we use HAL.  Here multiple users cannot use the same hardware simultaneously. Examples of HAL virtualization tools include VMware, Denali, and XEN.

Operating System Level

At the Operating System Level, the virtualization model creates an abstraction layer between the operating system and the application. This layer acts as an isolated container on the operating system and the physical server.

This is commonly useful when there are multiple users, and no one wants to share hardware. Each user gets their virtual environment using a dedicated virtual hardware resource, eliminating conflicts. Examples of this level are Jail, Virtual environment, and FVM.

Library Support Level

Library virtualization is applicable when operating system-level virtualization is cumbersome, as applications use APIs from libraries at a user level. These APIs are well-documented, making library virtualization suitable for scenarios where applications need to communicate with the system.

API hooks control the communication link from the application to the system. Examples of this level are Wine and Wabi.

User-Application Level

Application-level virtualization is used when only one application needs to be virtualised. In this case, there is no need to virtualise the entire environment of the platform. This approach is generally used when running virtual machines that use high-level languages.

The application sits above the virtualization layer, which in turn sits on the application program. It lets the high-level language programs compiled be used at the application level of the virtual machine to run seamlessly. Examples of this level are JVM and .NET.

Which Virtualization Layer is the Most Complex to Implement?

When it comes to implementation of the layers of virtualization, then it involves varying degrees of complexity depending on the layer. Generally, hardware and OS support produce the highest performance. However, hardware and user-application levels are the costliest to implement. 

Achieving user isolation is the most challenging aspect of virtualization implementation. The choice of virtualization layer depends on the specific requirements of the organisation, balancing performance, cost, and isolation needs.

Conclusion

Virtualization is a crucial technology in cloud computing, enabling efficient resource utilisation and application flexibility. The implementation of virtualization involves different layers, including ISA, HAL, Operating System, Library Support, and User-Application Levels. Each layer addresses different aspects of resource abstraction and offers unique advantages.

While hardware and OS support offer the highest performance, they are also the most complex and costly to implement. Understanding these layers and their trade-offs is essential for designing and managing virtualised environments effectively.

Frequently Asked Questions

What is virtualization in Cloud Computing, and Why is it Important?

virtualization creates virtual versions of hardware, enabling multiple operating systems to run on a single physical machine, enhancing resource utilisation and flexibility.

What are the Main Types of Virtualization Implementation?

The main types include full virtualization, para-virtualization, and OS-level virtualization, each offering different levels of hardware abstraction and performance.

How Does Full Virtualization Differ from Para-virtualization?

Full virtualization simulates the hardware completely, allowing unmodified operating systems, while para-virtualization requires modifications to the guest OS for better performance.

What is OS-level virtualization, and What are Its Common Uses?

OS-level virtualization, or containerization, virtualizes the operating system, allowing multiple isolated user-space instances to run on a single OS kernel. It finds application in environments where multiple applications need to run in isolation.

What are the Different Levels of Implementation of Virtualization?

Virtualization is applicable at ISA, HAL, Operating System, Library Support, and User-Application Levels, each addressing different aspects of resource abstraction