A virtual machine (VM) is defined as a computer system emulation, where VM software replaces physical computing infrastructure/hardware with software to provide an environment for deploying applications and performing other app-related tasks. This article explains the meaning and functionality of virtual machines, along with a list of the best VM software you can use.
What Is a Virtual Machine?
A virtual machine (VM) is a computer system emulation. VM software replaces physical computing infrastructure/hardware with software to provide an environment for deploying applications and performing other app-related tasks.
The term “virtual machine” (VM) refers to a computer that exists only in digital form. The actual computer is often referred to as the “host” in these situations, while other operating system(s) running on it are referred to as the “guests.” Using the hardware resources of the host, virtual machines let users install more than one operating system (OS) on the same computer.
Virtual machines are also used to develop and publish apps to the cloud, run software that is not compatible with the host operating system, and back up existing operating systems. Developers may also use them to test their products quickly and easily in different environments. VM technology can be used both on-premises and within the cloud. For example, public cloud services often use virtual machines to give multiple users access to low-cost virtual application resources.
How do virtual machines work?
Virtualization allows for creating a software-based computer with dedicated amounts of memory, storage, and CPU from the host computer. This process is managed by hypervisor software. As needed, the hypervisor moves resources from the host to the guest. It also schedules operations in VMs to avoid conflicts and interference when using resources.
A virtual machine (VM) allows a different operating system to be executed inside the confines of its distinct computing environment within a window similar to those used for other programs. As it is often separated from the rest of the system, the virtual machine cannot make any unapproved modifications to the host computer. This is done to prevent the virtual machine from interfering with the central operating system of the host.
Benefits of using virtual machines
Organizations, IT professionals, developers, and other home users looking for ways to solve problems that result from remote operations are set to benefit from what virtual machines offer. Virtual machines provide users with the same applications, settings, and user interfaces they would find in a physical computer from a remote area. Other benefits include:
- Cost savings: VMs eliminate upfront costs of expensive hardware, such as those involved in acquiring physical servers for hosting applications. Organizations can acquire better hardware that provides platforms for virtual environments and storage that cost significantly less than continuously acquiring bulky hardware.
- Energy savings: Thanks to virtualization, businesses can operate several virtual PC environments on a single physical computer. This can effectively cut down on the total energy spent as multiple operating systems (OS) are run on one computer instead of several. Consequently, organizations spend less electricity to run their physical servers during operations and cooling. This makes them somewhat environmentally friendly as they contribute to reducing their carbon footprint.
- The isolated environment provided by virtual machines: VMs give testers, developers, and security analysts a virtual environment where they can safely run multiple applications and services in a separate space. For instance, a security analyst can run various scenarios for different operating systems, such as Windows or Linux, to test their product on one computer using VMs. This increases their productivity.
- Easy to backup and clone: Physical servers take up significantly more time to replace in cases of catastrophic events than virtualized environments which may take a couple of minutes. Also, because virtual machines are stored on the hard drives of the host, they are easy to back up, move, or copy in real-time.
- Save space: Virtual machines help organizations reduce unnecessary hardware machines such as servers. In turn, this may lead to organizations using fewer floor spaces and cabling, thus lowering costs to invest in more critical areas. Virtual machines also have the potential to store more data for a lesser price than using physical servers.
- Flexibility: Virtual machines enable organizations to run multiple operating systems simultaneously. With the help of VMs, organizations and developers can buy any type of desktop and use an operating system of their choice without worrying about the compatibility of the programs they may require. This allows them flexibility as they can efficiently run Microsoft Office on a macOS.
- Workplace mobility and customization: Different departments in an organization can configure their virtual machine as necessary. Through the creation of virtual desktops, employees can work remotely and collaborate with their colleagues without having to show up in their offices to use their systems physically. This promotes productivity in the workplace and may lead to cost-cutting for organizations looking to switch to remote working.
Types of Virtual Machines
Virtual machines can be of two types — i.e., system VMs and process VMs.
1. System virtual machines
These kinds of VMs are completely virtualized to replace a real machine. The way they virtualize depends on a hypervisor — such as VMware ESXi, which can operate on an operating system or bare hardware.
The hardware resources of the host can be shared and managed by more than one virtual machine. This makes it possible to create more than one environment on the host system. Even though these environments are on the same physical host, they are kept separate. This lets several single-tasking operating systems share resources concurrently.
Different VMs on a single computer operating system can share memories by applying memory overcommitment systems. This way, users can share memory pages with identical content among multiple virtual machines on the same host, which is helpful, especially for read-only pages.
The key advantages of system VMs are:
- System virtual machines have the capability, either via emulators or by using just-in-time compilation, of providing a simulated hardware environment. This environment is distinct from the instruction set architecture of the host (ISA).
- The virtual machine software users choose comes packed with application provisioning that allows users to create packages, high availability, maintenance, and disaster recovery. This makes the tools for virtual machines more straightforward to use, making it possible for many operating systems to operate effectively on a single host.
- The presence of a virtual partition allows for multiple OS environments to co-exist on the same primary drive. This partition allows for sharing files generated from the host or the guest operating environment. Other processes, such as software installations, wireless connections, and remote replications, such as printing, can be performed efficiently in the host’s or guest’s environment.
- It allows developers to perform tasks without changing operating systems. All the generated data is stored on the host’s hard drive.
Disadvantages of system virtual machines are:
- When virtual machines indirectly access the host’s hard drive, they become less efficient than actual machines.
- Depending on the system, the performance of several virtual machines running on the same host can be different. The speed of execution and the protection against malware can also vary, leading to unstable behavior. Users can mitigate this problem using virtual machine software that provides temporal isolation.
- The guest operating system may not necessarily be compatible with the malware protections provided by the host resources. Therefore, it may require additional separate software leading to increased costs.
2. Process virtual machines
These virtual machines are sometimes called application virtual machines or Managed Runtime Environments (MREs). They run as standard applications inside the host’s operating system, supporting a single process. It is triggered to launch when the process starts and destroyed when it exits. It offers a platform-independent programming environment to the process, allowing it to execute similarly on any platform.
Process virtual machines are implemented using interpreters and they provide high-level abstractions. They are often used with Java programming language, which uses Java virtual machines to execute programs. There can be two more examples of process VMs — i.e., the Parrot virtual machine and the .NET Framework that runs on the Common Language Runtime VM. Additionally, they operate as an abstraction layer for any computer language being used.
A process virtual machine may, under some circumstances, take on the role of an abstraction layer between its users and the underlying communication mechanisms of a computer cluster. In place of a single process, such a virtual machine (VM) for a process consists of one method for each real computer that is part of the cluster.
Special case process VMs enable programmers to concentrate on the algorithm instead of the communication process provided by the virtual machine OS and the interconnect.
These VMs are based on an existing language, so they don’t come with a specific programming language. Their systems provide bindings for several programming languages, such as Fortran and C. In contrast to other process VMs, they can enter all OS services and aren’t limited by the system model. Therefore, it cannot be categorized strictly as virtual machines.
See More: Top 10 DevOps Automation Tools in 2021
Top 10 Virtual Machine Software
A superior VN application facilitates the use of many operating systems on a computer. Users should consider what features they may require when choosing what VM software suits them best. The following is a list of the top 10 virtual machine software to use:
1. VMware Workstation Player
VMware Workstation Player is recognized as a virtualization solution that supports a variety of operating systems on a single machine without requiring a reboot. It allows for seamless data sharing between hosts and guests and is designed for IT professionals. The following are features of VMware Workstation Player:
- Users can access hundreds of supported guest and host operating systems and may acquire a license for business usage.
- It is compatible with WSL2, Windows 10’s Hyper-V, Credential Guard, and Device Guard capabilities.
- It supports better DirectX 11 3D graphics capability and 8GB of GPU RAM.
- It supports platforms such as 64-bit Windows and Linux operating systems, Ubuntu, and CentOS.
2. Parallels Desktops
Parallel Desktop software provides hardware visualization for Windows to run on Mac without rebooting, and their applications are the most powerful, fastest, and easiest for doing this. The following are features of Parallels Desktops:
- It enables switching from Mac to Windows with a single click.
- It delivers data such as consumption statistics and licensing actions in real time.
- It has no complex keyboard shortcuts making it easier to use.
- It supports platforms such as Windows 11,10,8.1, and 7, Linux, and macOS.
Like several other options on this list, this is also an open-source hypervisor. It works on x86 computers and is suitable for home or enterprise use that runs on Linux, Windows, etc. The following are features of VirtualBox:
- It gives the PC the ability to execute any application.
- It enables individuals to operate several OS concurrently on the same hardware.
- It allows users to resize their windows and has the drag and drop function.
- It supports platforms such as Linux, Windows, Solaris, and OpenSolaris.
4. OracleVM VirtualBox
OracleVM VirtualBox is an open-source X86 and AMD64 virtualization product for home and enterprise use. The following are features of OracleVM VirtualBox:
- It has an intuitive layout and provides a guide to adding new virtual managers.
- It provides high performance for enterprise users and is highly compatible with most windows versions.
- It offers advanced modularity, 3D virtualization, and remote machine display.
- It supports platforms such as Solaris, macOS, Linux, Windows 10,8.1, Server 2012, Server 2016, etc.
5. Citrix Hypervisor
Citrix Hypervisor simplifies operational administration to enable users to conduct intense tasks in a virtualized environment. It is best for Windows 10. The following are features of Citrix Hypervisor:
- It gives users support for enhanced graphic workloads.
- Users can easily enjoy a secure environment to store, access, and work on large files.
- Its users can access apps and desktops from any device in any public cloud.
- It supports platforms such as Windows 10, Server 2016, Some Linux, and specific Ubuntu versions.
See More: DevOps Roadmap: 7-Step Complete Guide
6. Red Hat Virtualization
It is an open-source platform that offers centralized management and enables its users to create new VMs. Additionally, one may utilize the method to replicate existing ones and see how everything works together. The following are features of Red Hat Virtualization.
- It is straightforward to configure, use, and administer.
- It is open source, so it is cost-effective and allows for integration with different systems as needed.
- It delivers high performance to Linux, Kubernetes, and cloud environments.
- It supports platforms such as Linux and Windows.
7. Hyper – V
Hyper-V is a hypervisor that enables the creation of virtual computers on x86-64-based systems. It may connect individual virtual computers to more than one network through setup. The following are features of Hyper-V:
- It supports a cloud-based platform that allows for the easy creation and removal of different operating systems.
- It allows for hardware virtualization.
- It supports platforms such as Windows, FreeBSD, CentOS, Linux, Red Hat Linux, Ubuntu, SUSE, and Debian guest OS.
8. Kernel Virtual Machine (KVM)
Kernel Virtual Machine enables end-to-end virtualization for Linux. It was designed to operate on x86 hardware with virtualization features. KVM has two core components: the main virtualization infra and a processor-specific module. The following are features of the Kernel Virtual Machine:
- It provides reduced latency and increased prioritizing.
- Every virtual machine has its own private virtualized hardware.
- It assists users with scheduling and resource management. It supports platforms such as Windows, Linux, FreeBSD, OS X, React OS, Linux, and Solaris.
9. Proxmox Virtual Environment
Proxmox Virtual Environment integrates networking, KVM hypervisor, and Linux (LXC) container capabilities on a single platform. The following are features of Proxmox Virtual Environment:
- It enables the creation and management of lightweight containers.
- It helps combine two virtualization techniques into one platform.
- It gives users maximum flexibility in their production environment.
- It supports platforms such as Safari, Chrome, and Firefox on windows and Mac devices.
10. Quick Emulator (QEMU)
QEMU is a common and open-source emulator and virtualization machine. Its system is written using C language. It allows the building of virtual worlds for many architectures and operating systems at no cost. The following are features of QEMU:
- It offers hardware virtualization.
- It supports running multiple OS on any system and has no host OS restriction.
- By running guest code on the host CPU, KVM can execute with near-native performance.
- It supports platforms such as OpenBSD, FreeBSD, Solaris’s host Os, Windows, Linux, and Mac.
According to a 2022 report by Market Data Forecast, the global VM market was worth $3.5 billion in 2020. This is poised to grow further as enterprises rely more on software-based technologies (like the cloud) and reduce their hardware footprint. Indeed, virtual machines can go a long way in helping to optimize IT costs and also provide a safe environment for application security testing and cybersecurity checks.
MORE ON DEVOPS
- What Is DevOps? Definition, Goals, Methodology, and Best Practices
- What Is DevOps Lifecycle? Definition, Key Components, and Management Best Practices
- What Is DevSecOps? Definition, Pipeline, Framework, and Best Practices for 2022
- Top 18 Azure DevOps Interview Questions in 2022
- What Is an API (Application Programming Interface)? Meaning, Working, Types, Protocols, and Examples