Xen Server is a specialized platform that uses hardware virtualization technology in its solutions . It is worth noting the fact that in this case it is impossible to find any cardinal differences from the software procedure, but the performance is quite comparable with the productivity of a real machine, which made this base so popular for use in an industrial environment.
What are the benefits?
Among the main advantages of using Xen Server are the following:
- A significant reduction in time, as well as the complexity of developing virtualization systems, which is achieved by providing hardware interfaces for managing the necessary guest systems.
- Providing users with the ability to significantly increase the performance of virtualization platforms due to the fact that guest systems are managed directly through the hypervisor.
- Such platforms are much more protected from external interference, because they use an extremely clear separation of the virtual machines themselves, as well as the used hardware resources. The work of each platform is carried out in complete independence from other equipment, that is, all units operate in their space using individual resources.
- Among other things, Xen Server differs in platform independence of the created guest systems from the host computer.
What is he like?
Xen itself is a cross-platform hypervisor. This platform is a unique development, which belongs to the University of Cambridge and today is distributed exclusively under the GPL-license. Initially, two main branches of the product were supported - the commercial version and the version with the source code, but in 2009 it was said that all versions of Xen Server will be absolutely free, that is, the resource will become free.
The main idea of such a hypervisor is a domain, that is, a pre-launched version of a virtual machine. In the event that it starts to reboot, the domain is completely completed, and after the second download a new one is formed. Even during the migration process, Xen Server content will be copied between them. Due to this, in the process of its existence, almost every virtual machine ends up in the queue in various resources, however, Xen operates only directly with the concept of the domain, and everything else appears only after it comes to providing administration of applications that provide control over hypervisor.
Why is the system so widespread?
Today, we can safely say that the Citrix Xen Server is one of the most powerful systems with hardware virtualization support. It is worth noting that it remains the fastest and most secure among all the types presented, but it is a completely free product. However, of course, it cannot be said that this solution is recognized as absolutely universal, and therefore, in some situations, users can also resort to other types of software.
How to install and configure it?
Citrix Xen Server is designed to provide more efficient operation of standard Windows and Linux operating systems. It is worth noting that you can also use other platform options, but the manufacturer does not give any guarantees that normal operation will be noted on them.
You can download all the necessary files from the official website of the developer, and we recommend that you familiarize yourself with the basic terms of use and the license agreement in advance. After you download Citrix Xen Server and write it to a specific drive, you can connect the device to the computer and start working. Immediately it is worth noting the fact that during this installation any data that you stored on your disk will be completely deleted, so you must take care in advance to ensure the safety of important information.
You will then see a screen that prompts you to install Xen Server 6.2 (or another version if you downloaded it). After passing through the simple installation steps, a final window will appear, indicating that the installation of the platform has been carried out correctly.
After the final download of Xen Server to Ubuntu Server or other types of platforms, the user automatically switches to the main window of an already running system. It looks like a full-fledged main menu of the loaded Xen-system, and at the same time it is divided into two columns, where in the left you can select the main parameters by using the cursor keys, while in the right you will see all the relevant options, with which you can change certain properties of a working system. To go to such a change, you need to select the desired item and click on Enter.
While you are in the control window of Xen Ubuntu Server, you can use the Alt + F3 key combination to switch to the standard Linux console, which once again proves that this platform itself is a standard Linux, equipped with its own utilities, and also an understandable and well-known to many command set. For this reason, for those people who own the Linux operating system, there is nothing difficult in getting used to the basic features of this platform very quickly.
Customize the system
After you start this server, using the appropriate address in your browser you can look at two main links. One at a time you can download XenCenter, with the help of which full control of this platform is provided, while the other is an exe-file. One way or another, after installation, you will see the management console after you enter your own host address and root password in it, and you will be granted access to the system.
Getting basic information
In the standard mode of the running host, you can view both statistical and technical information, and by sorting the tabs at the top you can also get access to a large number of other additional ratings and parameters. For example, in the Performance tab, you can see basic information about how currently loaded is the Xen Server host machine that you just deployed to, and how free resources are used.
Install the guest system
If you want to put the guest system on the host, you will need to go to the New VM item or just VM, and after opening this menu item, select the operating system that you are going to install as the guest. In particular, if you wish, you can also install Xen Server on Windows 7. It is worth noting that this platform offers a fairly wide variety, and the installation procedure is almost completely identical to that used in VMware Workstation. That is, the process is divided into several main stages:
- determination of the type of system;
- setting the required number of processors and memory;
- freeing up space on the hard drive or a specialized storage medium for installing a new system in it.
If you have ever had experience with VMware Workstation in your life, you can be sure that you can easily understand the basic functions and you can easily configure and initially install Xen Server on Windows 7 or other types of operating systems.
What to do next?
After you create and start a new machine, the procedure becomes completely standard for installing the operating system that you choose. And there are no completely new elements. You just have to wait until the installation of the new system is completed, after which you can fully use the functions of the Xen Server console. Deploying VDI or launching any other mechanisms - all this is now within your capabilities, and you can use the system as you see fit.
Hardware
Do not forget that the operation of the system directly depends on the hardware you use. For this reason, the primary task before creating any cloud is to provide servers on which the virtualization procedure will be carried out.
In order to ensure sufficiently fast migration between different IBMs, a specialized switch is used as part of the stand, which theoretically allows you to accelerate migration by 10 times, but in practice this acceleration is an order of magnitude less. In order to provide access to the local network of servers and virtual machines, an additional switch can be added to the stand, with the help of which traffic will be transmitted to external clients.
Among other things, it is also important to use uninterruptible power supplies, which will ensure the correct restoration of processes on the server in case of failure of the central power supply.
How to position the server?
The next question is where exactly will the virtual machines be stored . In the event that they will be located exclusively on the servers themselves, this will negatively affect the overall reliability of the entire system, since in case of any malfunctions you will have to automatically lose all the virtual machines hosted on this equipment.
Among other things, do not forget that using this approach will also greatly complicate the overall task of balancing the load, since to ensure the migration of the virtual machine, you will initially need to move its disk to some other server, and this will create a rather long and tedious procedure.
Create a virtual network infrastructure
In order to provide yourself with the ability to flexibly manage the network settings of virtual machines, as well as to make sure that they are not in the same subnet as the Xen Server, you will need to establish a virtual network infrastructure. At the same time, Citrix initially envisioned such a problem and developed DVSC, which also appears as a virtual machine, but already consumes significantly less RAM and resources.
If you go directly to the DVSC web-interface, you will find quite a lot of useful information about network infrastructure, including a list of virtual machines that have managed to connect to a specific network at the moment, all kinds of error messages, and network activity graphs only for a specific virtual machine, but also in principle for the entire network.
You can also use DVSC as a standard firewall, the rules of which can be set through the AccessControl tab. The network security policy is divided into four levels, and the rules allow you to describe a specific type of action, a protocol (in which the sender and receiver ports can be specified, as well as already known protocols), as well as who this rule will be applied to.