KVM Virtualization Guide [Use Cases, Advantages, and How it Compares with OpenVZ]

The strength of KVM is its seamless interaction with the Linux kernel, which gives its virtualization capabilities a solid base. KVM guarantees the best speed and security for guest VMs by utilizing hardware virtualization extensions like Intel VT-x or AMD-V. By giving each VM its own isolated instance of an operating system under this complete virtualization strategy, a wide variety of OS support, including Linux, Windows, and BSD, is made possible.

KVM also has cutting-edge capabilities like live migration, dynamic resource allocation, and snapshotting, which add to its appeal. Live migration makes it possible to migrate operating virtual machines across hosts without interruption, which makes workload balance and maintenance activities easier. Dynamic resource allocation makes ensuring that system resources are used effectively and are adjusted to the changing needs of VMs. Snapshotting, on the other hand, gives administrators the power to record VM states at particular moments, giving speedy backup or recovery alternatives.

KVM’s open-source nature fosters a thriving developer and system administrator community, fostering ongoing innovation and support. KVM offers the flexibility and scalability necessary to satisfy various virtualization needs, from small-scale installations to large-scale cloud settings.

This article explores the fundamental ideas, benefits, and standout aspects of KVM virtualization in greater detail. Businesses may streamline operations, maximize resource utilization, and create the foundation for a virtualization strategy that is ready for the future by realizing the full potential of KVM.

What is KVM Virtualization?

Linux-based systems can virtualize their hardware using KVM (Kernel-based Virtual Machine), an open-source technology. Multiple virtual machines (VMs) may operate on a single physical host due to this complete virtualization solution. KVM makes use of hardware virtualization extensions like Intel VT-x or AMD-V to deliver effective and secure virtualization capabilities.

KVM is a Linux kernel module that, at its heart, transforms the host computer into a hypervisor, enabling it to control and execute several guest virtual machines (VMs). Due to KVM’s direct access to the host’s hardware due to this integration with the kernel, guest VM performance is almost identical to that of native hardware.

Support for a variety of operating systems is one of KVM’s key benefits. Numerous guest operating systems, including variants of Linux, Windows, BSD, and others, can be run on it. KVM is ideal for a wide range of use cases, from server consolidation to cloud computing, due to its versatility.

As KVM offers full virtualization, each guest VM is able to run a separate virtual instance of the operating system. By ensuring complete independence between the guest VMs and the host system, isolation improves security and stability. The KVM hypervisor controls the virtualized CPUs, memory, discs, and network interfaces that are exclusive to each VM.

The support for hardware acceleration that KVM offers is another noteworthy feature. KVM delivers outstanding performance by enabling guest virtual machines (VMs) to directly access the physical hardware resources of the host computer by utilizing the hardware virtualization extensions present in contemporary CPUs. This method greatly enhances the performance of virtualized workloads by doing away with the necessity for difficult software emulation.

Also, KVM provides cutting-edge technologies that improve its management and use. A running VM can be smoothly relocated from one physical host to another without any discernible downtime due to a critical feature called live migration. This makes it possible for administrators to carry out maintenance procedures, distribute workload among hosts, or address hardware issues without interfering with the operating VMs.

Another crucial component of KVM is the distribution of dynamic resources. It enables the dynamic allocation and modification of system resources, like as CPU and memory, according to the requirements of the VMs. This guarantees effective resource use and makes it possible for virtualized systems to be more scalable and responsive.

A tool called snapshotting enables administrators to quickly and completely record the state of VMs at any given moment. This is very helpful for creating checkpoints before making large changes to a VM or for backup purposes. In the event of faults or system failures, snapshots offer a quick recovery alternative that is simple to restore.

Use Cases of KVM

The following are some typical KVM (Kernel-based Virtual Machine) use cases:

  • Server Consolidation: By operating several virtual machines on a single physical host, KVM efficiently facilitates server consolidation. As a result, management is made simpler, hardware expenses are decreased, and resource utilization is maximized.
  • Software development and testing: Software¬†benefit greatly from the environment that KVM offers. To test software compatibility, carry out debugging, and validate configurations without affecting the production environment, developers can build virtual machines that replicate different production environments.
  • Cloud computing: To offer Infrastructure-as-a-Service (IaaS) solutions, KVM is frequently utilized in cloud computing platforms. By creating and managing virtualized instances, service providers can provide clients with scalable and on-demand computing resources.
  • Disaster Recovery: KVM works well in disaster recovery settings due to its live migration functionality. KVM offers rapid failover and minimizes downtime during crucial scenarios, assuring business continuity. Running VMs can be moved easily from one host to another.
  • Visualization: KVM can be used to create virtual desktop infrastructure (VDI), which enables desktop virtualization. Businesses may be able to manage desktops more centrally, improve security, and provide employees flexible access to virtual desktops as a result.
  • Education and Training: To give students and trainees practical experience in a virtualized environment, KVM is frequently utilized in educational institutions and training settings. Without the requirement for specialized real hardware, it enables quick setup of numerous virtual machines for educational purposes.
  • High-Performance Computing (HPC): In HPC environments, physical resources can be partitioned into virtual machines and tasked with different computational tasks using KVM. As a result, resource management is more efficient, scalability is increased, and HPC cluster utilization is higher.
  • Deployment: The deployment of virtual appliances, which are pre-configured virtual machine images containing particular software or services, is frequently done using KVM. Applications can be deployed more easily, installations and configuration take less time, and a consistent runtime environment is provided via virtual appliances.
  • Testing and QA Process: KVM server provides a scalable, cost-effective option for software testing and quality assurance (QA) activities. Testing teams can create and manage many VMs with different configurations and software versions to test apps on a variety of platforms and environments.
  • Educational and investigation projects: For academic and research projects that demand virtualized environments, KVM is used. It makes it possible for researchers and students to test out alternative configurations, examine system behavior, and evaluate cutting-edge technology in a secure environment.

These are only a few of the many different applications that KVM virtualization can be used for. It is a flexible solution for a variety of computing demands due to its performance, flexibility, and rich feature set.

KVM vs.OpenVZ Virtualization

Two alternative virtualization systems, KVM (Kernel-based Virtual Machine) and OpenVZ, each have their own methods and characteristics. The following table contrasts KVM vs. OpenVZ:

Virtualization Techniques

KVM: KVM is an all-inclusive virtualization solution that provides complete hardware emulation and executes guest operating systems as separate instances. Each guest VM runs a unique kernel and functions independently from the host and other VMs.

OpenVZ, on the other hand, uses the idea of operating system-level virtualization and is a container-based virtualization solution. A single Linux kernel is used to build isolated containers, commonly referred to as “virtual private servers” (VPS) that share the same host kernel but have different user spaces.

Utilization of Assets

Each KVM VM uses its own kernel and system resources, so it provides total isolation and gives administrators more precise control over resource management. However, running several instances of the kernel also means that there is some overhead in terms of memory and CPU utilization.

OpenVZ: Compared to KVM, OpenVZ containers utilize resources more effectively because they share the same kernel. Containers provide resource sharing and dynamic resource allocation, improving host scalability and increasing the density of virtual instances. For some specialized workloads, this shared approach may, however, lead to restricted flexibility.

Support for Operating Systems:

KVM supports running a variety of guest virtual machines, including Linux, Windows, BSD, and other operating systems. High levels of compatibility are offered, and running unmodified guest OS instances is permitted.

OpenVZ: Because it uses the same host kernel as Linux, OpenVZ can only run Linux-based guest containers. For some applications that need particular operating systems or versions, the requirement that the guest OS be compatible with the host’s kernel version can be a restriction.

Isolation and security:

KVM: The full virtualization strategy of KVM provides solid isolation between guest virtual machines (VMs) and the host system. Because each VM runs separately, there is no interference or security breach between the VMs. It works well in situations when security and tight isolation are essential.

Although OpenVZ offers effective container isolation, each container must use the same kernel. Due to the shared kernel design, if the host kernel is hacked, it may have an impact on all containers that are currently operating on the host. OpenVZ, on the other hand, offers isolation at the process level within containers, preventing conflict between different applications.

Scalability and management

KVM: Tools and frameworks that offer strong management capabilities, such as libvirt and virt-manager, are extensively used to support KVM. It offers capabilities like live migration for workload balancing and maintenance and is highly suited for handling large-scale virtualization infrastructures.

OpenVZ: OpenVZ offers a simple and lightweight administrative interface. Through the use of tools like vzctl and Virtuozzo Power Panel, management is made simpler. In contrast to KVM, managing a large number of containers can be challenging, and there might be scalability issues.

Is KVM a Container?

It is incorrect to say that KVM (Kernel-based Virtual Machine) uses container technology. Virtual machines (VMs) are created and managed on a host system by KVM, a complete virtualization solution. With full hardware emulation and isolation, it executes guest operating systems as separate instances. Each virtual machine (VM) running under KVM has its own kernel, enabling it to function independently from the host and other VMs.

On the other hand, containers use operating system-level virtualization, such as that provided by tools like Docker and Kubernetes. Although they have separate user areas, containers share the same host kernel. They offer quick and effective process and application isolation, enabling the use of isolated environments without the use of full virtualization.

While KVM and containers both support virtualization, their methods, levels of isolation, resource usage, and administration paradigms are different. While containers concentrate on facilitating lightweight application and service separation, KVM focuses on building and managing virtual machines.

Key Advantages of KVM Virtualization

KVM (Kernel-based Virtual Machine) virtualization’s principal benefits are:

  • Hardware Support: KVM makes use of hardware virtualization extensions included in contemporary CPUs, such as Intel VT-x or AMD-V. Due to the efficient and direct access to the host’s hardware resources made possible by this, guest virtual machines run nearly as well as native ones.
  • Operating System Flexibility: KVM supports a wide range of operating systems as guest virtual machines (VMs), including Linux, Windows, BSD, and others. It enables the use of unaltered guest operating systems, giving you the freedom to select the OS that is most suited for the various workloads.
  • Strong Security with KVM: KVM provides strong isolation between guests and the host system. In its own virtualized environment, each VM operates independently of the host and other VMs. By preventing any conflicts or unauthorized access between various VMs, this isolation improves security.
  • Ecosystem: KVM enjoys the advantages of a robust ecosystem of management tools and frameworks. A high-level API and command-line interface are provided for controlling VMs and their resources by tools like libvirt. Additionally, there are numerous graphical user interfaces (GUIs) that provide user-friendly management interfaces for KVM-based virtual machines, such virt-manager and Kimchi.
  • Open-Source: KVM is an open-source virtualization technology, making it freely accessible and backed by a sizable and engaged user and developer community. The open-source nature of the technology guarantees ongoing development, frequent upgrades, and broad community support.
  • Performance and Scalability: KVM has high scalability, enabling the deployment and administration of sizable virtualized environments. It is designed to make efficient use of system resources, providing virtual machines with excellent performance and resource distribution.
  • Integration into the Linux Ecosystem: KVM is simple to integrate into the Linux ecosystem. It delivers enhanced performance, stability, and compatibility with other tools and technologies that are also based on Linux as a result of its inclusion into the Linux kernel.

These benefits make KVM a popular solution for a variety of virtualized use cases, from server consolidation to cloud computing, and they help to explain its wide industry adoption.


For constructing and maintaining virtual machines, KVM (Kernel-based Virtual Machine) virtualization provides a reliable and adaptable solution. Its use of hardware virtualization extensions guarantees quick access to host resources, giving guest VMs nearly native performance. KVM offers flexibility in selecting the best OS for various workloads because it supports a large variety of OSs. Data protection is improved, and conflicts between VMs are avoided because to its robust isolation and security features. Modern capabilities like snapshotting, live migration, and dynamic resource allocation that allow high availability, resource optimized performance, and simple recovery from backups are also available with KVM. KVM, a scalable and high-performance virtualization solution for various computing situations, is supported by a vast ecosystem of management tools, a thriving open-source community, and seamless integration with the Linux environment.

  • June 7, 2023