what is linux kvm

In Linux, kvm's full name is "Kernel-based Virtual Machine", which is an open source system virtualization module; KVM can help developers transform Linux into a virtual machine monitoring program, allowing the host computer to run multiple Isolated virtual environment.

#The operating environment of this tutorial: linux5.9.8 system, Dell G3 computer.

linux kvm (kernel-based virtual machine)

kvm is Kernel-based Virtual Machine, an open source system virtualization module. It is an open source virtualization technology built into Linux and has been integrated into all major Linux distributions since Linux 2.6.20.

KVM helps you turn Linux into a hypervisor, enabling a host computer to run multiple isolated virtual environments, known as virtual guests or virtual machines (VMs).

It uses Linux's own scheduler for management, so compared to Xen, its core source code is very small. KVM has now become one of the mainstream VMMs in academia.

KVM virtualization requires hardware support (such as Intel VT technology or AMD V technology). It is a complete virtualization based on hardware. In the early days of Xen, it was Para-Virtualization based on software simulation, while the new version is based on full virtualization supported by hardware. However, Xen itself has its own process scheduler, storage management module, etc., so the code is relatively large. The widely circulated commercial system virtualization software VMware ESX series is Full-Virtualization based on software simulation.

How does KVM work?

KVM turns Linux into a Type 1 (bare metal recovery) hypervisor. All hypervisors require some operating system-level components to run virtual machines, such as memory managers, process schedulers, input/output (I/O) stacks, device drivers, security managers, and network stacks. Since KVM is part of the Linux kernel, it has all of these components. Each virtual machine is implemented like a normal Linux process, scheduled by the standard Linux scheduler, and uses specialized virtual hardware such as network cards, graphics adapters, CPUs, memory, disks, etc.

Prerequisites for installing KVM:

1. Make sure the machine has VT

Terminal input command: grep vmx /proc/cpuinfo (INTEL chip)

grep svm /proc/cpuinfo (AMD chip)

If you don’t know the manufacturer of the chip, enter: egrep '(vmx|svm)' /proc/cpuinfo

If Flags: If there is vmx or svm in it, it means that VT is supported; if there is no output, it means that your CPU does not support it and the KVM virtual machine will not be successfully installed.

2. Make sure VT is turned on in the BIOS

Intel(R) Virtualization Tech [Enabled]

If necessary, you also need to turn on VT-d

# in the BIOS ##3. Make sure the kernel version is newer and supports KVM

Use uname -r to check the kernel version. If the Linux version is below 2.6.20, you need to upgrade the kernel.

Summary:

Generally speaking, it is a virtual machine software that can create a new virtual machine under Linux; compared with VMware, Linux’s KVM technology has native Kernel support is relatively faster than VMware. If you are using the desktop version of Ubuntu/CentOS, it is recommended to use KVM to install the virtual machine directly. There is no need to add an additional layer of VMware.

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