What is a virtual machine? 3 types of virtual hostings
Want to know everything about the virtual machines? Read the article to find out. We'll discuss how virtual machine works, tell about all types of server virtualization and give links to the best virtual machine hosts.
Table of contents
- How does a virtual machine work
- How to use personal virtual machines
- Pros and cons of the virtual machines
- Best apps to create Virtual machines on different OSes
- Server-side virtual machines
- Pros and cons of server virtualization
- What can be virtualized
- Types of server virtualization
- Types of virtual hostings
- How to choose virtual machine hosting
- Best virtual machine hosts
Simply put, a virtual machine or VM is a simulation of a computer inside another computer. It is an artificial programmable environment that makes it possible to imitate a fully functional operating system on top of the one already installed on your device.
They are mostly used by developers who have to deal with different workspaces based on different software platforms and test their projects using a variety of tools that are not always cross-platform. Also, VM’s are popular among enthusiasts who are eager to try out specific Linux distributives.
How does a virtual machine work
Typically, you have a host machine and a guest machine. A host machine is a computer whose hardware will be used as a basis for virtual “devices”. The guest machine is an artificial computer that takes part of the real hardware and ties it together as a structure to run the operating system.
You can create several guest machines and run them on one host. For instance, installing Ubuntu Linux and Windows 10 on an Apple computer and using it in parallel as you would do with two real devices. They are less powerful and a bit restricted in their capabilities but in essence not really different from actual computers.
How to use personal virtual machines
There are several ways to launch a VM on your hardware. Usually, it resembles installing a special application (VMWare or Parallels Desktop) and choosing an operating system to download on it. A bit of mouse clicking without any hassle. Simple as that.
The interfaces of such apps are quite user-friendly so you won’t struggle even if you have no experience of working with virtual machines. If you know how to install OS on a real device then you know how to do it with a virtual one. Moreover, they all have great documentation which will help to get things done right.
Pros and cons of the virtual machines
The biggest advantage of VMs is the opportunity to work with an isolated operating system without sacrificing the one you already have installed.
It means that you have the essence of another PC without actually buying another PC. Furthermore, it is easy to deploy. Just a few clicks and the new virtual machine is ready to use. No USB sticks, no rebooting, no hard disk partitioning, no time-consuming setting up, or other frustrating things to worry about.
What you will have to sacrifice is performance. Virtual machines tend to be slower than real computers. Even if you have a reasonably powerful PC with 32Gb of RAM and an 8-core chip, you won’t be able to use all its potential, and artificial devices will struggle to perform some tasks.
Best apps to create Virtual machines on different OSes
If you want to run virtual machines on Linux, we would recommend you try out the cross-platform and the open-source application VirtualBox. It was created by Oracle.. This app is free and runs really well on Linux-based OSes. As an alternative, you might consider an app called Boxes created by the developers of Gnome Desktop and Gnome OS.
For those of you who consider yoursleves a Mac-person, we’d recommend an application called Parallels Desktop. It is native, the most advanced and performant virtual machine on Mac with features like quick OS-install. But it is a bit pricey. As an alternative, you might want to install VirtualBox.
Windows users usually prefer VMware Workstation. It is one of the most powerful solutions to quickly create and maintain functional and reliable virtual machines. It uses all the underlying Windows technologies to achieve the best performance for guest OSes. It is the best virtual machine for Windows 10 and if you don’t want to pay you can use a restricted free version called VMware Player that will be enough to install some Linux distributions and try them out.
Server-side virtual machines
When we talk about server-side virtualization, we usually mean a huge set of technologies and practices that help engineers decompose complex infrastructures, make them secure, make them more reliable, and much more cost effective to use on a large scale in today’s IT industry.
Normally, server virtualization implies techs used by a business. And there are many ways people at large corporations utilize virtualization. Creating a large number of tools to simplify a variety of tasks and create brand new tools based on virtualization technologies.
And there are many engineers around the globe who have spoken about this. Like Matthew Portnoy, author of a book called Virtualization Essentials, who once said:
«Virtualization in computing often refers to the abstraction of some physical component into a logical object. By virtualizing an object, you can obtain some greater measure of utility from the resource the object provides. For example, Virtual LANs (local area networks), or VLANs, provide greater network performance and improved manageability by being separated from the physical hardware».
Pros and cons of server virtualization
Let’s talk about the advantages and disadvantages of using a virtual machine on a server.
The main thing which should be considered an advantage of virtual machines on servers is the price of such technology. It helps to make hosting websites, databases, and web applications cheaper. Create artificial networks and subsystems. Additionally, it helps developers around the world to deploy their project in a few quick clicks without ordering real hardware and spending time configuring it.
Speaking of cons we must say that there are few disadvantages of virtual machines. The most noticeable drawbacks are:
lack of security (as with some types of virtualization)
and lack of performance (while using options with modest payment plans).
What can be virtualized?
Virtualization is a broad term that can be defined in a variety of ways depending on the purpose of a given type of virtualization. That’s why you often stumble upon titles like “Application virtualization”, “Storage virtualization”, etc.
Some sources claim that you can only find five types of virtualization, while others believe there are seven. We will discuss just four that are used most regularly (and are closely connected with the term VM) and explain the difference between different types of virtualization in general.
Small virtual machine representing a single product encapsulated with its dependencies. You can create a virtual copy of an app installed on the remote PC and use it as if it was installed on your device. Some types of application-level virtualization make it possible to use only the hardware of the host machine, but some utilize the resources of both guest and host computers.
This type of virtualization helps businesses around the world to store massive amounts of data and home users to divide hard drives into virtual sections for personal convenience.
Yep, when you partition off the disk you are virtualizing storage making it easier to isolate files from each other but physically they exist on the same hardware.
Large companies do the opposite. They bind thousands of real disks into one massive virtual one.
We already discussed this type of virtualization at the beginning of the article. OS simulation implies using virtual machines on the server to create digital workspaces.
Virtual machines installed on top of the remote machine can be considered a platform to develop applications on and test them out. Furthermore, such virtualization is popular among webmasters and server administrators who use VMs on the servers for maximum control.
You’ve probably heard of this one. Virtual private networks (or VPN’s) are often used in enterprise areas and sometimes by generic customers for more specific purposes.
Virtual networks help large companies create private webspace inside the internet. This private network is accessible via special software and makes it possible for team members to live across multiple continents but work together as if the whole party were sitting inside one office using the local network.
Furthermore, a VPN is used to imitate the webspace of different countries, so users can access websites and applications that are not available in the country they live in.
Types of server virtualization
Above, we’ve peeped into what things can be virtualized. Below, we will talk about different types of virtualization. Most specialists divide them into three groups (but you may find more on the web). All imply specific relationships between the hardware of the host machine (a real one) and the software of the guest machine (a virtual one). So, it is important to pinpoint that when we speak about virtualization types, we don’t touch on the technological realization of things.
The first type is the easiest to understand. Full virtualization means creating some kind of virtual machine that uses the real hardware of the host machine exclusively and at the same time becomes completely isolated from it. This kind of virtualization makes the process of creating and maintaining VMs more compatible and portable. It is easier to launch a fully functional OS on top of the host using full virtualization. But at the same time, this type of virtualization is less performant than its modern alternatives like para or OS-level technics widely used today.
OS-level virtualization (containerization)
This kind of virtualization is useful when you need to create instances of an operating system or certain applications within an already running OS. It provides administrators with the tools that allow the quick deployment of many containers (OSes or apps), scale them, port, copy, reorganize, etc.
But at the same time, containerization in some cases makes the whole platform less secure and stable (but it is not true in the case of Docker, for example).
When virtual machines are controlled via an application called hypervisor, they are called para-virtualized. It means that they use a specific layer of software between the RAM, CPU and software of the guest OS. This layer helps them to get the necessary part of the hardware to launch the OS and apps and run them smoothly.
It is time to discuss more specific essences like real applications and sets of tools that are used in the virtualization area to create VMs on different host systems.
These software products are quite similar to the ones we reviewed above but they were created precisely for the use of administrators and developers who run VMs on remote servers. We will review four popular solutions used by hosting providers to virtualize fully-fledged OSes on the machines in their data centers.
ESXi is a hypervisor developed by VMWare, one of the pioneers in the industry of creating and configuring VMs. What makes ESXi popular is the opportunity to install a virtual machine right on top of the real hardware, neutralizing the software layer between the hypervisor and the host machine. Because of its approach ESXi easily becomes one of the quickest and performant technologies to work with even though it has some disadvantages because of used technics. ESXi brings a user-friendly graphical interface to manipulate the VMS and advanced mechanisms that allow administrators of guest systems to deploy identical systems on other hardware platforms easily without any delays and glitches.
OpenVZ is a technology that demonstrates how OS-level virtualization could work. The biggest advantage of OpenVZ is the ability to create many cheap Linux-based virtual workspaces with the capabilities of real servers but there are too many drawbacks you will encounter using this software:
It can incorrectly distribute resources between many virtual machines.
It makes it impossible for users to have any impact on the core of the system.
It only supports Linux and there’s no way to use any other OS.
It is not as secure as most of the concurrent software products.
Xen is a cross-platform hypervisor that is also an open-source project. Xen is absolutely free, it is compact and easy to install on any Linux distributive or FreeBSD.
The biggest advantage of Xen is the ability to use para-virtualization. That is why most VMs built with Xen run much faster and demonstrate impressive reliability. Speaking of disadvantages we might consider the lack of a graphical interface and not so the user-friendly interface to control the VMs. It can be quite hard to cope with Xen especially if you’re a novice in this area.
KVM is a technology built into the Linux kernel. One of the most powerful and functional platforms to date. It allows every VM hosted on the computer to have its own kernel. Because of the layer of technologies that lie in the foundation of KVM, it is possible to create VMs that are performant, isolated, secure, and not really restricted in terms of functionality. Even though KVM is based on Linux it is possible to launch Windows as a guest operating system.
Types of virtual hostings
Described technologies are used to create and support hosting products. Servers with virtualization are the most prevalent option now and they are extremely important for hosting providers because they simultaneously lower the price of the servers and raise the performance of cloud computing solutions.
At the moment, we have three hosting categories that you can use as a platform for your applications.
The cheapest way to host a website on the web. Renting shared hosting you get access to containers launched inside a Linux-based operating system that generally works as a small bit of storage on the SSD also used by tenants using the same host as you. It is possible to deploy a fully functional static website using shared hosting as a platform, but you should be ready to deal with all the caveats that OpenVZ technology brings such as a not infrequent lack of hardware resources to run the deployed project smoothly.
Virtual Private Servers are mostly created using technologies like KVM. They are independent and isolated OSes inside the host machine. VPSes can provide users with all the benefits of a KVM such as an opportunity to deploy dynamic web applications, store massive databases, install and use Windows Server as a digital workspace, etc.
One of the reasons why VDSes became extremely popular is the price. It costs much less than a dedicated server but provides almost identical capabilities that you would usually expect from a real computer. KVM-based virtual machines even make it possible to influence the kernel of the OS.
A modern solution that ideally suits projects of any size and complexity. The biggest plus of cloud-based systems is scalability. You can gradually make it grow with the functionality of your app and the audience that uses it.
Cloud hosting is a network of computers around the world developed using the most advanced technologies available. That’s why it is the most performant and secure way to create any virtualized products (workspaces, VPNs, digital data storage, etc.).
How to choose virtual machine hosting?
The choice depends on the demands of your project. You can use the cheapest option to deploy a static site but if you want something more powerful and useful you’ll have to get over to VDS or a cloud-based solution.
Also, we strongly recommend paying for the hosting because cheap virtual machine hosting providers exist but free ones are mostly run by crooks. It might also be dangerous to host any project on free hosting.
Best virtual machine hosts
- Digital Ocean — one of the most popular hosting providers that offer reliable machines for any use. Well-balanced in terms of price and functionality. A good choice for experienced developers and administrators.
- Netlify — easy to use hosting that can automatically convert GitHub projects into running applications.
- Hostman — an advanced alternative to Netlify that not only offers an opportunity to deploy apps using GitHub and GitLab repositories but also provides customers with a set of pre-made servers.
- InMotion — a powerful VPS host that can boast 99.99% uptime. It works almost 24/7 without interruptions so your project will be accessible to your customers most of the time.
- IONOS — the cheapest web hosting for virtual machines that makes it possible to create your own VM for just $1.
Here it is. Now you know how virtualization works, why you need to install a virtual machine and how to do this. We recommend trying out demo versions of apps like VMware and Parallels to decide which one will become your go-to solution. If you’re trying to find the best server to host a VM you might want to read our article about the 8 best VPS hosts.
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