Virtualization is a technology that can be used to create virtual representations of servers, storage, networks, and other physical devices. Virtual software emulates the functionality of physical hardware to run virtual machines simultaneously on the same physical machine. Businesses use virtualization to efficiently use hardware resources and get additional returns on their investment. It also provides cloud computing services that help organizations effectively manage their architecture.
Why is virtualization important?
By using virtualization, you can interact with any hardware resource with greater flexibility. Physical servers consume electricity, take up storage space, and require maintenance. Access to them is often limited by physical proximity and network design. Virtualization allows you to eliminate all these limitations by abstracting the functionality of the physical hardware of the software. You can monitor, maintain, and use your hardware infrastructure as a web application.
An example of virtualization
Consider a company that needs servers to perform three functions:
- secure storage of corporate e-mail;
- launch of client programs;
- running internal business applications.
Each of these features has different configuration requirements.
- Email programs require a lot of storage and a Windows operating system.
- Client applications require a Linux operating system and high computing power to handle large amounts of website traffic.
- Internal business applications require iOS and a large amount of internal memory (RAM).
To meet these requirements, the company installs three different dedicated physical servers for each application. The company has to make a large initial investment and perform ongoing maintenance and upgrades one machine at a time. In addition, the company cannot optimize its computing power. It pays 100% of the cost of maintaining the servers, but only uses part of their storage and processing capacity.
Effective use of hardware
With the help of virtualization, the company creates three digital servers or virtual machines on one physical server. It defines the OS requirements for virtual machines and can use them as physical servers. However, the company now has less hardware and less associated costs.
Infrastructure as a service
A company can go further and use cloud instances (virtual machines from cloud providers that manage all the underlying hardware), and the company can choose server resources with different configurations. All applications run on these virtual servers and users do not notice any difference. Server management also becomes easier for company IT teams.
Principle of operation and key concepts of virtualization
To properly understand a kernel-based virtual machine (KVM), you first need to understand some basic virtualization concepts. Virtualization is a process that allows a computer to share its hardware resources with multiple digitally separated environments. Each virtualized environment operates within allocated resources such as memory, computing power, and storage. With virtualization, organizations can switch between different operating systems on the same server without rebooting.
Virtual machines and hypervisors are two important concepts of virtualization.
Virtual machine
A virtual machine is a software-defined computer that runs on a physical computer with a separate operating system and computing resources. A physical computer is called a host machine, and virtual machines are called guest machines. Several virtual machines can run on one physical machine. Virtual machines are abstracted from computer hardware using a hypervisor.
Hypervisor
A hypervisor is a software component that manages multiple virtual machines on a computer. This ensures that each virtual machine receives its allocated resources and does not interfere with other virtual machines. There are two types of hypervisors.
A hypervisor is virtualization software that is installed on computers. It is a software layer that acts as an intermediary between virtual machines and the host’s underlying hardware or operating system. Hypervisors coordinate access to the physical environment so that multiple virtual machines have access to their own share of physical resources.
For example, if a virtual machine needs computing resources, such as the processing power of a computer, the request is first sent to the hypervisor. The hypervisor then forwards the request to the underlying hardware, which executes the task.
Below are the two main types of hypervisors.
Hypervisors of the first type
Hypervisors of the first type, also known as hypervisors without an operating system, are hypervisor programs that are installed directly on the computer hardware, rather than on the operating system. Therefore, hypervisors of the first type have higher performance and are usually used in corporate applications. KVM uses a hypervisor of the first type to host multiple virtual machines of the Linux operating system.
Hypervisors of the second type
Hypervisors of the second type work as an application on computer hardware with an operating system. Hypervisors of the second type are suitable for the computing power of end users.
Comparison of cloud instances and virtual machines
The phrases “instance” and “virtual machine” (VM) are often used interchangeably, especially when it comes to cloud computing. However, there are differences: a software simulation of a real computer is called a virtual machine. Just like a real computer, it runs an operating system (OS) and programs. Virtualization software creates virtual machines (VMs), allowing many virtual machines to run on a single physical computer (host).
An instance is usually referred to as a virtual server that is provisioned and managed by a cloud provider. Although instances and virtual machines (VMs) run identical operating systems and applications, instances are typically created using preconfigured templates provided by the cloud provider. Instances are managed through an API or cloud management console and are part of a wider cloud infrastructure.
What are the benefits of virtualization?
Virtualization provides a number of benefits for any organization.
Effective use of resources
Virtualization increases the efficiency of hardware resources used in data centers. For example, instead of running a single server on a single computer system, you can create a pool of virtual servers on the same computer system, using and returning servers to the pool as needed. Fewer underlying physical servers can free up data center space and save money on electricity, generators, and cooling devices.
Automated IT management
Now that physical computers have become virtual, it is possible to control them using software tools. Administrators create deployment and configuration programs to define virtual machine templates. You can continuously and consistently duplicate your infrastructure and avoid error-prone manual configuration.
Fast disaster recovery
When events such as natural disasters or cyber attacks negatively affect business operations, it can take hours or even days to restore access to IT infrastructure and replace or repair physical servers. And in a virtualized environment, this process takes only a few minutes. Responsiveness significantly increases fault tolerance and facilitates business continuity so that operations can continue on schedule.
What are the types of virtualization?
Virtualization technology can be used to gain the functionality of many different types of physical infrastructure and all the benefits of a virtualized environment. You can go beyond virtual machines and create a collection of virtual resources in your virtual environment.
Server virtualization
Server virtualization is the process of dividing a physical server into several virtual ones. This is an effective and economical way of using server resources and deploying IT services in the organization. Without server virtualization, physical servers use only a small portion of their computing power, resulting in idle devices.
Storage virtualization
Storage virtualization combines the functions of physical storage devices such as network attached storage (NAS) and storage area networks (SAN). You can combine storage equipment in a data center, even if it is from different manufacturers or different types. Storage virtualization takes all of your physical media and creates a large virtual storage that can be assigned and controlled with management software. IT administrators can streamline storage operations such as archiving, backup, and recovery by virtually consolidating multiple network storage devices into one.
Network virtualization
Any computer network consists of such hardware elements as switches, routers and firewalls. An organization with branches in different geographic regions may use several different network technologies that together form a corporate network. Network virtualization is the process of combining all these network resources to provide centralized execution of administrative tasks. Administrators can configure and control these elements virtually without touching the physical components, significantly simplifying network management.
Next, two approaches to network virtualization are presented.
Software-defined networks
Software-defined networking (SDN) manages the routing of traffic by taking over routing control from the routing of data in the physical environment. For example, to ensure consistent call quality across all online meetings, you can program your system to prioritize video call traffic over application traffic.
Virtualization of network functions
Network function virtualization technology combines the functions of network devices such as firewalls, load balancers, and traffic analyzers, working together to improve network performance.
Data virtualization
Today’s organizations collect data from multiple sources and store it in different formats. They can also store data in different locations, such as cloud infrastructure and on-premises data center. Data virtualization creates a software layer between that data and the applications that need it. Data virtualization tools process application data requests and return results in the appropriate format. Thus, organizations use data virtualization solutions to increase the flexibility of data integration and provide support for cross-functional data analysis.
Virtualization of programs
Virtualization allows applications to run on operating systems other than those for which they were designed. For example, users can run a Microsoft Windows application on Linux without changing its configuration. Follow the guidelines below to achieve application virtualization.
- Streaming programs. Users stream the application from a remote server, so it only runs on the end user’s device when needed.
- Virtualization of server programs. Users can access the remote application from their browser or client interface without installing it.
- Virtualization of local programs. The application code comes with its own environment to ensure that it runs on all operating systems without modification.
Desktop virtualization
Most organizations have non-technical staff who use desktop operating systems to run common business applications. In particular, it can be such employees as:
- Customer Service, which requires Windows 11 desktops and customer relationship management software;
- a marketing team that needs Windows 10 for sales applications.
You can use desktop virtualization to run different desktop operating systems on virtual machines that your teams can access remotely. This type of virtualization provides efficient and secure desktop management, saving you money on desktop hardware. Below are the types of desktop virtualization.
Infrastructure of virtual desktops
Virtual Desktop Infrastructure runs virtual desktops on a remote server. Users can access them using client devices.
Virtualization of local desktops
Virtualization of local desktops means running hypervisors on local computers and creating virtual computers with a different operating system. You can switch between local and virtual environments in the same way as between applications.
How does virtualization differ from cloud computing?
Cloud computing refers to the on-demand delivery of computing resources via the Internet on a pay-as-you-go basis. Instead of purchasing, maintaining and owning physical data centers, you can access technology services such as computing power, storage and databases through cloud service providers as needed.
Virtualization technology facilitates the implementation of cloud computing. Cloud service providers build and maintain their own data centers. They create different virtual environments that use the underlying hardware resources. You can then program your system to access these cloud resources using APIs. Your infrastructure needs can be met as a fully managed service.
How does server virtualization differ from containerization?
Containerization is a way of deploying application code to run in any physical or virtual environment without modification. Developers link application code with appropriate libraries, configuration files, and other dependencies that the code needs to run. This single software package, called a container, can run independently on any platform. Containerization is a type of application virtualization.
Server virtualization is like building a road to connect two places. It is necessary to recreate the entire virtual environment, and then run your program in it. In comparison, containerization is like building a helicopter that can fly to any of these places. Your application resides inside a container and can run in any type of physical or virtual environment.
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