What is the Xen Hypervisor?
Virtualization is done to divide a computer’s resources, and if you are dealing with this field, you have come across the term Hypervisor Xen virtualization by now.
Virtualization is the technique virtual server providers use to create powerful versions of a physical server. Xen is one of the most famous of them, which increases the flexibility of servers with techniques such as parallelization. Its excellent performance in sharing hardware between virtual servers balances the load.
A computer divided between several users means a virtual machine, but if a server is divided between several users, it means a virtual server. No need to worry; below, we will talk in detail about all the topics you need to know about virtualization and Xen virtualizer. So let’s get started:
What is meant by virtualization?
Virtualization allows you to divide the capabilities of a physical machine between multiple users or environments and use its total capacity.
The virtualization hypervisor acts as a divider and can be placed on the operating system or directly in the hardware. In this way, hyper wires take the system’s physical resources and, by dividing them according to needs, provide conditions so virtual machines can use them.
There are many reasons for using the virtualization technique, the most common of which is using different operating systems on one computer. Of course, server virtualization is also beneficial. Server administrators use this technique to divide an extensive system into smaller parts because this increases the efficiency of the system and the processes related to each virtual machine. Keep separate.
If you are interested in getting more information in this field, you can read the article “What is the concept of server virtualization?”
Hypervisor Xen virtualization
Xen is an open-source hypervisor based on Linux that uses the paravirtualization method for virtualization. As a type 1 hypervisor with security level c2, Xen hypervisor can be installed directly on the computer hardware without the need for a host operating system and directly controls, monitors, and manages the hardware, peripheral resources, and I/O.
Virtual machines request this hypervisor to provide them with the required resources. Of course, these machines must first install the Xen virtual device driver to access the hardware components. So, the overall role of the Xen Hypervisor is to coordinate the interaction between virtual machines and physical hardware.
It is better to talk a little about paravirtualization so that the following topics related to the Xen virtualizer fit better:
paravirtualization virtualization
Paravirtualization is an advanced version of virtualization technology that helps improve performance, more accessible backups, faster migrations, and reduces energy consumption. This method uses hyper call operation instead of binary translation at compile time. Hypercar is a software trap called from the domain to access the hypervisor. Agitated call for hypervisor is the same as syscall for operating systems. With these types of calls, privileged requests that require the cooperation of the hypervisor are sent.
Paravirtualization requires admin manipulation because the host operating system must be modified. Also, the host operating system can communicate directly with the hypervisor using drivers.
Of course, this virtualization method related to Xen Hypervisor does not perform well in terms of portability and compatibility.
Xen virtualization architecture
Xen is a microkernel hypervisor that separates policy from mechanism. As shown in the figure below, this hypervisor implements tools and assigns all security policies to domain 0 or Dum0. Note that the control domain or domain 0 is also considered a virtual machine. In general, it does not include any device drivers locally and provides a mechanism by which the guest operating system can directly access physical devices.
This makes the size of the Xen Hypervisor relatively small and is placed between the hardware and the operating system.
The primary implementation of a Xen system
A control domain, the Xen hypervisor, and several virtual machines are the main components of a Xen-based virtualization environment. Of course, the tools, commands, and configuration files are part of this system through which virtualization management is done.
The physical computer that hosts these components is called the virtual machine host server. All these components, in cooperation with each other, create a platform that hosts virtual machines.
Hypervisor Xen
This hypervisor, which is sometimes called a virtual machine monitor, performs the task of coordinating the interaction between virtual machines and hardware. IT managers can run multiple operating systems on hardware using this hypervisor.
Examining the page table, allocating resources for new domains, and scheduling domains are among the tasks of this hypervisor.
Domain 0 or control
This is the first domain launched by the Xen Hypervisor at boot time and is responsible for direct hardware access and management of shared hardware resources related to virtual machines. If this domain is hacked, the hacker can control the entire system. Therefore, particular security policies are needed to improve habitat 0 security. This domain allows users to easily create, copy, save, modify, share, and restore operations on their virtual machines. This domain itself consists of several components:
SUSE Linux Enterprise Server: A graphical and command-line environment for managing virtual machines.
QEMU: An open-source tool for simulating computer system components such as processors and other equipment and virtualizing them.
Guest virtual machine or DomU
Unlike domain 0, this domain does not have direct access to the hardware and must run FrontendDriver to access the desired section multiplexed. DomU is started by domain 0, and the user accesses it from the command line.
The guest virtual machine consists of the following components:
- At least one virtual disk has a bootable operating system. A virtual disk can be based on a file, partition, or any other type of block.
- One configuration file per guest virtual machine
- Multiple network devices connect to a virtual network that provides domain control.
Advantages and disadvantages of Xen Hypervisor virtualization
Advantages:
1) The combination of hardware-based virtualization and paravirtualization increases the flexibility and optimal performance of the system.
2) Workload balancing by capturing the memory, CPU, and disk I/O to help improve performance and manage data density.
3) The feature of Citrix storage link allows the system administrator to use the features of the arrays of large companies such as Netapp, Dell Equal logic, etc.
4) Support for the following features is one of the strengths of this virtualizer:
- Multiprocessing
- Ability to transfer from one car to another
- Tools to convert a physical server to a virtual machine or a virtual server to the virtual machine
- Centralized management of multiple servers
- Windows and Linux system performance monitoring in real-time
Disadvantages
1) Xen is more reliable for Linux systems than Windows.
2) The management of parts such as drives, memory, backup, recovery, and fault tolerance depends on a third-party component.
3) Over time, deploying Xen on a Linux kernel can become burdensome.
4) Sometimes, this virtualization increases the load on resources with high input/output rates, resulting in a lack of resources for other virtual machines.
What is a Xen server?
Xen server is an open-source platform for cloud, server, and desktop virtualization, with the help of which organizations can virtualize even the most intense workloads and automated management processes in less than 10 minutes, and as a result of using It increases flexibility and reduces costs.
This Xen Hypervisor-based platform is developed by Citrix Systems and can run on all x86 processors. This software integrates the computing power of a physical server into several virtual machines, are simulated as a standard server. This platform’s monitoring part helps the user easily manage the allocation and distribution of physical server computing resources between virtual machines and monitor their performance.
Support for most server operating systems, such as Linux and Windows, means that meeting the operational needs of a standard server is not limited. This software is available in 3 free, legal, and enterprise versions.
Indeed, by reading this section, you understood how servers are virtualized and provided to users. Of course, many alternatives to Xen have their advantages and disadvantages. The complete independence of the virtual server from other virtual servers is one of the strong points of this platform, which makes the user benefit from all the facilities.
* If you need a virtual server that can easily handle simple to heavy processes to achieve better performance or more productivity in your business and pay an affordable fee for it.
Conclusion
By using Xen Hypervisor, the user can run multiple operating systems on the host computers, and virtualizing them allows them all to benefit from the same hardware resources. Servers that have the virtual state of a physical server are also created during this simulation and virtualization process. This platform’s benefits are increasing flexibility, reducing costs, and improving system performance.
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