Virtualization. What’s that?

Virtualization is a way of providing computing power unified by software logic, abstracted from hardware. The main objective of virtualization is to isolate from each other computational processes or sets of specific activities that occur within a single device. Accordingly, the method is suitable in areas where you want to minimize hardware but maximize software capabilities. For example, in data centers, hosting. Even in workplaces in a large organization.

Main types of virtualization

The method is universally adopted for a number of reasons:

• high level of security;

• saving technical resources;

• fairly simple hypervisor configuration.

Obviously, the key aspect is economics, for the Jew is alive in everyone. Since virtualization allowed not to purchase a huge amount of hardware, but to provide computing resources remotely, there were many people who wanted to close technical needs in this way. So, what are the different types?

Emulation

We encounter this kind of virtualization all the time. By the way, never run a Sega emulator on your computer? Or a smartphone? Yes, essentially emulating another device on one device. From the perspective of the software running in the emulator, we’re playing a Sega game, while in reality we’re looking at a smartphone, sitting from a laptop or tablet. In general, whatever your heart desires, as long as it’s software. This type of virtualization is useful and quite common, because it’s easier to run an emulator than to buy a device.

Memory virtualization

It’s the type that ordinary mortals don’t see very often. There is a computer with 32GB of RAM. There are 10 computers that only have 16GB each. The app gobbles up all 32 GB of memory, but all PCs are required to work with it. What to do? That’s right, turn a computer with 32GB into a shared cache whose memory other computers will use for their own benefit.

Should we make it harder? If so, we pool all the DRAM into a common pool, now it appears to all computers in the cluster that the DRAM population is equal to the sum of all the RAM in the cluster. This allows resource-intensive applications to be loaded within a single array. That’s an interesting way to do it. I’ll write more about him sometime.

Virtualization of operating systems

This type is quite common, for it is very convenient. It is found everywhere, and in a variety of variations:

1. Software virtualization. Have you run Windows applications from Linux and vice versa? If so, you already know what I’m implying. If not, I’ll explain. A software hypervisor is created. I’ll tell you what this beast is later, commands from the main OS are broadcast to the guest OS, the hypervisor is responsible for the correct interpretation of commands.

2. Hardware. In this case, there is hardware-level support; the hypervisor is installed underneath the system rather than on it. That is, it is the foundation, all operating systems are deployed on top of the hypervisor. In this case, you get operating systems that are really isolated from each other.

3. At the OS level. Simply several shells, conventionally abstracted from each other, doing work in parallel. There is no complete isolation in this case.

In general, this topic deserves a separate review. Lots of useful things to say.

Software virtualization

This type is designed to run software shells that are isolated from each other. Practically identical to the previous type. By its properties it resembles terminal access, but from the OS point of view it looks as if several applications are running, not just one. A separate process is allocated for each run of the same program.

File storage virtualization

If your goal is to present a set of drives as a single physical drive, then you will need to virtualize that way. There is block virtualization, which is most commonly found in SANs , and file virtualization, which is most prominent in NAS.

This can also include the following types:

1. File structure virtualization. This type allows you to create a data layer on top of existing disparate file systems. For example, make a single b for different OS on the network.

2. Distributed file system. Allows access to specific files and disks from different devices, with each structure displaying the drive as a logical drive. The most obvious example is a network drive.

3. Storage virtualization. For example, optical drive emulator, logical disks.

Data virtualization

Actually a method of abstracting ordered structures from the physical medium, form, structure. A very complex and fairly new topic for the IT world. Deserves a separate review. Let me explain in simple terms, there are several pools of information, thousands of databases, disparate, having different structure and media. Administration and operation will be difficult. But if you create a virtual platform that interprets the information and integrates it for further work, things get noticeably simpler.

Such a method has been used before, but now, due to the increasing complexity of data structures, is becoming more common.

Network virtualization

By combining technical and software resources into a single network we create a so-called virtual network. A network can be created either externally, connecting many diverse networks into a single virtual network, or internally, where a virtual network is simulated between software components internally.

In what areas is virtualization used?

In fact, there are quite a few areas where this technology is used. It’s worth highlighting the main ones, for there’s no point in listing all the individual cases. So let’s cut to the chase, no need to drag out an already long text.

Virtualization of views

It represents the launch of virtual desktops, but unlike a terminal server, the guest session is isolated from the others. By the way, very close spheres, the differences are minimal.

The main advantage is that one guest is unable to interfere with the space of another, which consequently eliminates critical errors, compatibility issues, and many other unpleasant aspects that are ubiquitous in terminal solutions. Each application is deployed in a virtualized isolated environment. All operations are performed by the virtualization server. The user only gets the result. In principle, except for the isolated environment for each application, there are no differences from terminal solutions.

The presentation method used is the same as in terminal solutions: thick or thin client – special devices designed for input/output of data is used for remote interaction with the virtualization server. Big power is not necessary, because often the use of virtualization of thin client applications is much cheaper than equipping the office with productive computers. Aside from the price, there are a number of other positives:

1. Easier to administer. You can prohibit copying to external media for individual users, track employee actions, distribute technical resources among employees by priority, and set automatic backup of all data.

2. It’s much easier to deal with licenses. If not all employees use the software at the same time, you can buy a license for connections or users. There will be a noticeable savings. And you’ll have to buy a separate license for each device.

3. Infrastructure centralization. This noticeably simplifies data collection and storage.

Application virtualization

Have to be used when a higher level of security is required. Any application can be run in an environment completely isolated from the operating system. Then you can easily check for viruses, vulnerabilities and avoid many unpleasant surprises.

Server virtualization

Simulating hardware at the software level is also possible. First, you need to install the hypervisor. The following complexes will do:

• VMware Workstation;

• Microsoft Hyper-V;

• OracleVM Server;

• Xen.

There are a number of other hypervisors. They all have their advantages and disadvantages. All in all, the topic is vast and deserves a separate article.

This complex is deployed “before” the installation of operating systems, after which it is customized and allows you to simulate certain technical characteristics, the presence of certain drivers, in general, you have a virtual machine, but with quite physical characteristics.

A single virtualization server can host many virtual machines that are completely isolated from each other. The most prominent example is the VPS (Virtual Server) hosting service. The benefits of this approach are clear:

1. High degree of protection. Virtual machines are isolated from each other. Exposure to viruses or misconfiguration in one virtual machine will not affect another. Of course, there are vulnerabilities that allow you to reach the hypervisor level, but the task is quite difficult.

2. Reduced consumption. Suppose you need a lot of low-powered machines. It’s expensive to take separately. After all, enclosures, rack space also cost money. It’s easier to take one powerful machine, set up emulation of the configurations you want, and run it. Significant space and cost savings.

3. Hypervisor-level administration greatly simplifies the management of the technical infrastructure.

4. Good level of scalability. You can create a cluster of appliances to increase the number of virtual machines.

Without disadvantages, unfortunately, you can not do without, you will have to put up with possible problems, although there are ways to solve them, but it is an additional investment:

1. Low fault tolerance. All technical resources are concentrated within a single device, in case of failure, everyone gets it. The only way out is to make a duplicating device, although this is quite expensive.

2. Complex sweep. Setting up a virtualization server is quite difficult. It takes a lot of time and being an experienced professional to do it right.

The rest of the disadvantages will vary depending on the goals. But, as you can see, it’s not without flaw.

Use

As you can see, for many tasks (if not most), virtualization will do the trick. You have already been introduced to the concept and now have an idea of the method. So, if you need to build a complex IT structure qualitatively and economically, you can use the approach given in the article. All the best, hope I was able to help!