VIRTUALIZATION AND HYPERVISOR
HYPERVISOR
A hypervisor or virtual machine manager (VMM) is computer software firmware or hardware that creates and runs virtual machines. A computer on which a hypervisor runs one or more virtual machines is called a host machine, and each virtual machine is called a guest machine. The hypervisor presents the guest operating systems with a virtual operating platform and manages the execution of the guest operating systems. Multiple instances of a variety of operating systems may share the virtualized hardware resources: for example, Linux, Windows, and macOS instances can all run on a single physical x86 machine.
TYPES OF HYPERVISOR
In their 1974 article, Formal Requirements for Virtualizable Third Generation Architectures, Gerald J. Popek and Robert P. Goldberg classified two types of hypervisor:
1.) Type 1 or Native and Bare Metal -
These hypervisors run directly on the host’s hardware to control the hardware and to manage guest operating systems. For this reason, they are sometimes called bare metal hypervisors. The first hypervisors, which IBM developed in the 1960s, were native hypervisors. These included the test software SIMMONand the CP/CMS operating system (the predecessor of IBM’s z/VM). Modern equivalents include AntsleOs, Xen, XCP-ng, Oracle VM Server for SPARC, Oracle VM Server for x86, Microsoft Hyper-V, Xbox One system software, and VMware ESX/ESXi.
2.) Type 2 or Hosted Hypervisor -
These hypervisors run on a conventional operating system (OS) just as other computer programs do. A guest operating system runs as a process on the host. Type-2 hypervisors abstract guest operating systems from the host operating system. VMware Workstation, VMware Player, VirtualBox, Parallels Desktop for Macand QEMU are examples of type-2 hypervisors.
Virtualization in Cloud Computing
Virtualization is the “creation of a virtual (rather than actual) version of something, such as a server, a desktop, a storage device, an operating system or network resources”.
BENEFITS OF VIRTUALIZATION
1.More flexible and efficient allocation of resources.
2.Enhance development productivity.
3.It lowers the cost of IT infrastructure.
4.Remote access and rapid scalibility.
5.High availability and disaster recovery.
6.Pay per use of the IT infrastructure on demand.
7.Enables running multiple operating system.
TYPES OF VIRTUALIZATION
- Hardware Virtualization.
- Operating system Virtualization.
- Server Virtualization.
- Storage Virtualization.
1) Hardware Virtualization:
When the virtual machine software or virtual machine manager (VMM) is directly installed on the hardware system is known as hardware virtualization.
The main job of hypervisor is to control and monitoring the processor, memory and other hardware resources.
After virtualization of hardware system we can install different operating system on it and run different applications on those OS.
Usage:
Hardware virtualization is mainly done for the server platforms, because controlling virtual machines is much easier than controlling a physical server.
2) Operating System Virtualization:
When the virtual machine software or virtual machine manager (VMM) is installed on the Host operating system instead of directly on the hardware system is known as operating system virtualization.
Usage:
Operating System Virtualization is mainly used for testing the applications on different platforms of OS.
3) Server Virtualization:
When the virtual machine software or virtual machine manager (VMM) is directly installed on the Server system is known as server virtualization.
Usage:
Server virtualization is done because a single physical server can be divided into multiple servers on the demand basis and for balancing the load.
4) Storage Virtualization:
Storage virtualization is the process of grouping the physical storage from multiple network storage devices so that it looks like a single storage device.
Storage virtualization is also implemented by using software applications.
Usage:
Storage virtualization is mainly done for back-up and recovery purposes.
How does virtualization work in cloud computing?
Virtualization plays a very important role in the cloud computing technology, normally in the cloud computing, users share the data present in the clouds like application etc, but actually with the help of virtualization users shares the Infrastructure.
The main usage of Virtualization Technology is to provide the applications with the standard versions to their cloud users, suppose if the next version of that application is released, then cloud provider has to provide the latest version to their cloud users and practically it is possible because it is more expensive.
To overcome this problem we use basically virtualization technology, By using virtualization, all severs and the software application which are required by other cloud providers are maintained by the third party people, and the cloud providers has to pay the money on monthly or annual basis.
