Last updated on May 1st, 2023 at 07:50 pm
The need for virtualization is relevant for many corporate systems, in this way you can save not only financial resources.
What is the KVM hypervisor
The KVM hypervisor (Kernel-based Virtual Machine) is Linux virtualization software running on different operating systems (OS). The program manages and distributes resources between all connected computers on which different OSs can stand. This allows you to run them simultaneously.
The software is open source. The hypervisor forms several copies of one computer (clones), each of which is perceived by users as an independent device.
On any of the virtual machines, it is possible to install a guest OS of the user, which is independent of the host hardware. The KVM hypervisor isolates operating systems, not allowing one of them to dominate the process of obtaining resources. However, if necessary, it will allow the OS of virtual machines to interact with each other, will ensure the exchange of files or other data between them.
At the same time, virtualization is understood as the technology of forming the presentation of a different number of PCs or servers based on one computer or server. This host has its own configuration of the processor, disk and RAM, and other parameters. Resources are distributed to independent virtual machines through special software.
The result is several computers that work independently, but in reality, they are a set of files that are stored in the host memory. But if the server is disconnected from the local network, then the hypervisor will cease to function and virtualization will be interrupted.
but also energy. Therefore, the development of this area is becoming a priority for organizations of various purposes and sizes.
KVM Virtualization Benefits :
- The ability to use a modified kernel of the OS and install your own distribution through your ISO image;
- Resources are in an independent position relative to each other;
- Support for a significant number of guest OS;
- Network card emulation, support for all protocols and firewall;
- VSN support drives virtual server management.
KVM virtualization on different operating systems
Initially, KVM virtualization was developed exclusively for Linux. In subsequent versions, support for a wide range of processors and OS was introduced, among which, in addition to Linux, the most famous are Windows, CentOS, Solaris, BSD.
KVM virtualization on different operating systems
Initially, KVM virtualization was developed exclusively for Linux. In subsequent versions, support for a wide range of processors and OS was introduced, among which, in addition to Linux, the most famous are Windows, CentOS, Solaris, BSD.
KVM on Linux
KVM is a virtualization module for the KVM Linux kernel on the x86 platform and supports hardware acceleration of Intel VT and AMD SVM. The kernel components required for functioning are installed on Linux version 2.6.20 and higher. The hypervisor includes a core that provides the core virtualization infrastructure and processor.
Some versions, like Ubuntu 18.04 or Debian, only support KVM hypervisors. Installation is simple and does not require much time. KVM is managed through the virsh utility. To make it convenient to work with a specific set of guest systems, the KVM must be configured in such a way that the hypervisor always assigns the same IP addresses.
KVM on Windows
Installing KVM virtualization on Windows is possible starting with OS version 10. You can download the ISO image from the official site, it is available in the trial version for a period of 30 days. The image is provided with a set of drivers for different guest operating systems, with a maximum capacity of 40 GB.
During installation, indicate the size of RAM, the number of cores, select or create a space for data and a new volume for the guest OS. The name of the virtual machine is registered only in Latin letters without spaces. The KVM interface is intuitive and the installation, as well as the setup, is not particularly difficult.
KVM on CentOS
Configuring the KVM hypervisor on CentOS requires additional installation of several packages that are not included in the basic version of the system. Download KVM virtualization at liberty. After rebooting the system, you need to check for the presence of the KVM and kvm_intel kernels.
To set up KVM vaults on CentOS 7, you can read the complete KVM virtualization guide, which is freely available on the Red Hat website. Ensuring reliable data storage is possible by installing the Raid I array. KVM hosting is performed in the address range 192.168.122.0/24.
KVM Security
Since the KVM virtual machine is developed on the basis of Linux, it inherits exactly this typical security model. SELinux adds the necessary parameters and means of forced access control and also applies multilevel security features. In addition, reliable isolation of used resources is provided.
Additionally, KVM security can be enhanced by installing antivirus software for virtual environments. Among the most common causes of failures, the human factor is noted: incorrect actions by the system administrator can lead to the fall of KVM servers and stop services.
Comparison with other hypervisors
Users often face the question of which virtualization to choose. Among the most common, in addition to KVM, are called Hyper-V, VMWare, OVZ, XEN and others. Each of them has its advantages and disadvantages.
Comparison of KVM and Hyper-V
Hyper-V is a system solution for providing hardware virtualization from Microsoft for 64-bit systems. It is presented in two versions of Standard and Datacenter, designed to ensure the operation of Windows operating systems. In the first version, you can connect only two servers with this OS, and in the second it is unlimited. But there are no restrictions on connecting Linux servers. The KVM server can run on all OSs.
By cons Hyper-V includes:
- Windows virtual machines must be licensed;
- There is no graphical interface (but a remote console is provided);
- There is no manufacturer support service, but the system can be updated regularly.
Cost. Virtual servers on Hyper-V are more expensive than on KVM.
Unlike KVM, Hyper-V does not require the installation of special drivers, so Hyper-V can be installed on any equipment.
Comparison of KVM and VMWare
The VMWare hypervisor is installed directly on the server. It has a convenient graphical console and a control monitoring system, interaction functions (setting ISO, rebooting, etc.). In addition to acquiring VMware vSphere 6, you will also have to buy licenses for each processor on the server, however, the memory size and the number of virtual machines do not affect the formation of the final cost.
VMWare also offers free options, but they have several limitations:
- Perhaps only reading the API;
- Virtual machines have up to eight cores;
- You can not make backups;
- You cannot connect to a service centre;
- No support for migration technology.
How and virtual machine KVM, VMWare products are supported by many operating systems: Linux, Windows, Solaris, Netware, FreeBSD, macOS and other.
KVM management is a little more difficult, since there is no transparent access to processes, files, the network interface and the console, and all this must be configured separately. The process of rebuilding individual parameters is also not entirely convenient, and it also requires a reboot of the OS.
Comparison of KVM and XEN
If you only need a server with an Intel-VT / AMD-V processor to connect the KVM hypervisor, installing XEN is a bit more difficult, since a modified kernel is required. They are on the most popular distributions of Debian, CentOS, Fedora.
The XEN hypervisor is one of cross-platform solutions and allows you to simultaneously connect multiple operating systems on the same computer. The main difference from analogs is the paravirtualization mode, which provides increased performance comparable in parameters with a real system.
Unlike KVM, XEN, if you do not need to connect machines to Windows or BDS, you do not need support for hardware virtualization. XEN cannot be used on Windows with a closed kernel, since you need to modify the kernel configuration of the guest OS. The system can be automated through scripts, but there is no graphical control program in the base package.
In terms of technical parameters, both types of virtualization are similar, but XEN is superior in its ability to support a large number of connected machines, backup and storage properties.
Comparison of KVM and OVZ
OpenVZ technology, like KVM, is based on the Linux kernel. With its help, independent standalone copies of the KVM OS of virtualization Ubuntu, Debian, CentOS are created on a single server, but other OSs cannot be installed, since virtual machines run on a collective Linux kernel.
OVZ is controlled from your personal account, from which you can automatically add the necessary resources: hard drive, memory, processor. Unlike KVM, in which the change in the tariff plan is possible exclusively upward, in OVZ you can transfer to another tariff with the same virtualization. Remote KVM allows you to change to a lower tariff, but with transfer to another server and with 1-2 hours waiting. In addition, the reconfiguration requires a reboot of the OS, and is not automatic, which complicates the process somewhat.
KVM hypervisors have more features and benefits, as a result of which tariffs are slightly higher.