Linux virtualization is the process of running one or more virtual machines on a physical computer, that is operated by the open source Linux operating system. Linux virtualization is used for creating virtual resources such as Operating system, server, network and storage device. It can be used for programming code, isolating specific apps, performance testing and security purposes.
The powerful hardware and computers made virtualization more practical for both server and desktop environments, helping to save power by combining several workspaces on one system and extending the workload that the computer can handle. The popular Linux virtualization solutions include QEMU, VMware, KVM, Xen and Virtual Box.
1.What are the different types of Virtualization?
The Virtualization can be used in different ways and various forms of virtualization are shown below:
- Hardware virtualization
- Server virtualization
- Application virtualization
- User virtualization
- Network virtualization
- Desktop virtualization
2.What are the types of Hardware virtualization?
The Hardware virtualization is categorized into two categories:
Full virtualization:
In order to run unmodified Partial virtualization, almost a complete simulation of the actual hardware is done to allow the software, which consists of a guest operating system.The Only few target environment is simulated. Thus,modification is needed for some programs to run in this virtual environment.
Para virtualization:
Here the hardware environment is not simulated, the guest programs are executed in their own isolated domains, like if they are running on a separate system. To run in this environment, the guest programs are required to be modified specifically.
3.What are the benefits of virtualization?
Virtualization is used for the creation of virtual machines and to manage them. It allows to share the resources with large amount of network resources. It contains lots of benefits and they are as follows:
- It does not depend on heavy hardware to run the application.
- It reduces the amount of space taken by both company data and data centers.
- It saves the amount of cost and helps to maintain easily.
- It combines the servers that are used for crashing.
- It offers multiple operating system run on one virtualization platform.
4.What is QEMU?
The QEMU is an open source and generic machine Virtualizer and emulator. It can achieve very good performance by using dynamic translation. The QEMU has the ability to run programs and OS that is made for one machine on a different machine, when used as a machine emulator.
5.What is KVM?
The KVM stands for Kernel Virtual Machine is a Linux Kernel module that provides a user space program to use the features of hardware virtualization of different processors.
6.What is virtual Machine Cloning?
The Virtual Machine Cloning is a process of creating a copy of an existing virtual machine with the same installed software and configuration as the original. The current virtual machine is known as the parent of the clone. After the completion of cloning operation, the clone becomes a separate virtual machine.
7.What are the types of cloning in virtualization?
A linked clone is a copy of a virtual machine, which shares the virtual disk with the parent virtual machine in a constant manner. This will occupy the space of the disk and provides multiple virtual machines to use the same installation of software.
A full clone does not depend on the copy of a virtual machine and after the cloning operation, shares nothing with the parent virtual machine. The operation of the full clone is entirely different from the parent virtual machine.
8.What is memory virtualization?
The memory virtualization aggregates the resources of the RAM from the networked systems into a single memory pool.
9.What is Storage virtualization?
The Storage virtualization is the method of extracting a logical storage from physical storage. A computer program,Virtual disk drive follows an optical disk drive or a hard disk drive in virtualized setup.
10.Define snapshot of a virtual machine?
The snapshot is the state of a virtual machine. Snapshots are taken just by giving order to be performed at a given time and can be returned on demand. With the conclusion that the VM appears exactly same, when the snapshot was taken. It is used as a rapid backup method.
11.What is the purpose of a Hypervisor?
The program that manages the virtual machine is known as Hypervisor. It provides multiple operating system to share a single hardware host. It also acts as a virtual machine manager, which manages many virtual machines. In this, each operating system has its own defined place, that consist of memory, processor and space. It helps to separate the layers between many operating systems, so that no one can get clash with one another. It is used as a controller program to control resources and host processors.
12.What are the different hypervisors available in Linux?
KVM and Xen are the two different hypervisors available in Linux.
13.What is the difference between KVM and Xen?
The KVM is the kernel based virtualization, so extra kernel is not required for this. It is a module In kernel and supports full virtualization. Whereas, for Xen hypervisor, first the Xen kernel has to be installed and have to enhance the machine with Xen kernel, it does not support full virtualization by default.
14.What is the use of virsh command?
The virsh command is used for managing the virtual machines depending upon Xen and KVM hypervisor. The virtual machines are identified by their domain names, on virsh interface. Hence Virsh is used to pause, create, list and shut down current domains
15.How to identify the KVM version?
The ‘virsh version’ command is used to find the KVM version.
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