The term 'Virtualization' can be used in many respect of computer. It is the process of creating a virtual environment of something which may include hardware platforms, storage devices, OS, network resources, etc. The cloud's virtualization mainly deals with the server virtualization and how it works and why it is termed so?
Virtualization is the ability which allows sharing the physical instance of a single application or resource among multiple organizations or users. This technique is done by assigning a name logically to all those physical resources & provides a pointer to those physical resources based on demand.
Over an existing operating system & hardware, we generally create a virtual machine which and above it we run other operating systems or applications. This is called Hardware Virtualization. The virtual machine provides a separate environment that is logically distinct from its underlying hardware. Here, the system or the machine is the host & virtual machine is the guest machine. This virtual environment is managed by a firmware which is termed as a hypervisor.
Figure - The Cloud's Virtualization:
There are several approaches or ways to virtualizes cloud servers.
- Grid Approach: where the processing workloads are distributed among different physical servers, and their results are then collected as one.
- OS - Level Virtualization: Here, multiple instances of an application can run in an isolated form on a single OS
- Hypervisor-based Virtualization: which is currently the most widely used technique
With hypervisor's virtualization, there are various sub-approaches to fulfill the goal to run multiple applications & other loads on a single physical host. A technique is used to allow virtual machines to move from one host to another without any requirement of shutting down. This technique is termed as "Live Migration". Another technique is used to actively load balance among multiple hosts to efficiently utilize those resources available in a virtual machine, and the concept is termed as Distributed Resource Scheduling or Dynamic Resource Scheduling.
Types of Virtualization
The virtualization of cloud has been categorized into four different types based on their characteristics. These are:
- Hardware Virtualization
- Full Virtualization
- Emulation Virtualization
- Software Virtualization
- OS Virtualization
- Server Virtualization
- Storage Virtualization
How Virtualization Works in Cloud
Virtualization plays a significant role in cloud technology and its working mechanism. Usually, what happens in the cloud - the users not only share the data that are located in the cloud like an application but also share their infrastructures with the help of virtualization. Virtualization is used mainly to provide applications with standard versions for the cloud customers & with the release of the latest version of an application the providers can efficiently provide that application to the cloud and its users and it is possible using virtualization only. By the use of this virtualization concept, all servers & software other cloud providers require those are maintained by a third-party, and the cloud provider pays them on a monthly or yearly basis.
In reality, most of the today's hypervisor make use of a combination of different types of hardware virtualization. Mainly virtualization means running multiple systems on a single machine but sharing all resources (hardware) & it helps to share IT resources to get benefit in the business field.
Difference Between Virtualization and Cloud
- Essentially there is a gap between these two terms, though cloud technology requires the concept of virtualization. Virtualization is a technology - it can also be treated as software that can manipulate hardware. Whereas cloud computing is a service which is the result of the manipulation.
- Virtualization is the foundation element of cloud computing whereas Cloud technology is the delivery of shared resources as a service-on-demand via the internet.
- Cloud is essentially made-up from the concept of virtualization.
Advantages of Virtualization
- The number of servers gets reduced by the use of virtualization concept
- Improve the ability of technology
- The business continuity also raised due to the use of virtualization
- It creates a mixed virtual environment
- Increase efficiency for development & test environment
- Lowers Total Cost of Ownership (TCO)
Features of Virtualization
- Partitioning: Multiple virtual servers can run on a physical server at the same time
- Encapsulation of data: All data on the virtual server including boot disks is encapsulated in a file format
- Isolation: The Virtual server running on the physical server are safely separated & don't affect each other
- Hardware Independence: When the virtual server runs, it can migrate to the different hardware platform