This educational blog answers the question, “What is the difference between KVM vs VMware?” and presents a high-level overview of integrating software-defined storage with kernel-based virtual machines (KVM) and VMware. For more technical information on Lightbits software-defined block storage, start with our product page.
The premise of this blog is to introduce the differences between KVM vs VMware. In general, VMware and KVM don’t natively integrate with each other, each is typically used in isolation. However, depending on the needs and the use case, that doesn’t have to be the case. Some tools and platforms can be employed to manage both within the same infrastructure,
The reader should understand that Lightbits high-performance elastic block storage seamlessly integrates with many virtualized environments–KVM, VMware, and Azure VMware Solution among them. What follows is more detailed information on the differences between KVM and VMware. I will also illustrate how software-defined storage can be integrated with each environment.
What Is VMware?
VMware is best known for its software products that enable virtualization. At the height of their usage, virtualization platforms like VMware revolutionized data center architecture because they fundamentally changed how applications consumed and managed resources, providing better isolation, security, portability, and application management. They did this by enabling multiple virtual machines (VMs) to run on a single physical computer, which improved resource utilization and flexibility. One of VMware’s most well-known products is VMware vSphere, a platform for managing virtualized data centers, offering services like compute, storage, and network management. VMware vSAN is a software-defined storage solution that integrates with vSphere for storage virtualization, while VMware NSX provides software-defined networking (SDN) capabilities. Until recently, VMware’s products have been widely used by enterprises to enable virtualized architecture and optimize IT infrastructure.
On November 22, 2023, Broadcom’s acquisition of VMware closed, marking one of the largest transactions in the technology sector. Following the acquisition, Broadcom restructured VMware into four divisions: VMware Cloud Foundation, Tanzu, Software-Defined Edge, and Application Networking and Security. In December 2023, VMware transitioned from offering perpetual licenses to subscription-based models for its products, including vSphere. Overall, Broadcom’s acquisition of VMware has led to significant organizational changes and product strategy shifts. While many organizations will continue to leverage VMware products, the disruption has caused many organizations to seek alternatives, including open-source solutions like KVM and migration to container-based architecture like OpenShift Virtualization.
What Is Kernel-Based Virtual Machine (KVM)?
KVM is an open-source virtualization software that turns the Linux® kernel into a hypervisor, enabling it to manage multiple VMs to run on the same physical server, each with its own operating system (OS) and resources.
What is a VM? A VM is a software application that acts as an independent computer within another physical computer.
What is a hypervisor? A hypervisor provides the foundation for your virtualization platform by pooling computing resources and reallocating them among virtual machines (VMs). Many options are available when choosing a hypervisor—two of which will be presented in this blog.
KVM-based virtualization refers to the use of KVM technology to create and manage KVM Kernel-based virtual machines on a Linux-based system.KVM is a Linux OS component that provides native support for VMs on Linux. It was merged into the mainline Linux in version 2.6.20, which was released in February 20071. Because KVM is integrated into the Linux kernel, it can leverage the kernel’s existing features for memory management, process scheduling, and hardware resource allocation to VMs, and it immediately benefits from every new Linux feature, fix, and advancement without additional engineering.
KVM Hypervisor Architecture
KVM is built into the Linux kernel, enabling it to act as a hypervisor. Linux kernel is the core of the open-source OS and a program that interacts with computer hardware. It ensures that software applications running on the OS receive the required computing resources. Linux distributions, such as Red Hat Enterprise Linux, Fedora, and Ubuntu, pack the Linux kernel into a user-friendly commercial OS.
Kernel-based virtual machines have all the needed OS-level components–memory and security managers, process scheduler, I/O and network stack, and device drivers–to run VMs. It requires a Linux kernel installation on a computer powered by a CPU that supports virtualization extensions, such as Intel VT-x or AMD-V, to provide efficient, high-performance virtualization. Each VM runs its own isolated operating system (like Linux, Windows, etc.), and the host OS (which must be Linux) controls these VMs through the KVM module. This allows for multiple independent environments to coexist on the same hardware.
KVM-based Virtualization Architecture
KVM vs VMware: Key Differences
What are the key differences between KVM vs VMware: both are virtualization technologies but differ significantly in architecture, licensing, and use cases. Both provide virtualization infrastructure to deploy bare-metal hypervisors on the Linux kernel. However, KVM is an open-source feature, while VMware is available via commercial licenses.
KVM is designed for Linux-based, open-source environments and is often used in cloud and data center implementations that prefer open-source solutions, such as OpenStack. KVM virtual machines are suitable for organizations seeking flexibility, customized setups, and lower costs. Because it’s a component of the Linux kernel, it takes advantage of Linux’s scheduler and memory management, making it highly efficient and can deliver near-native performance.
On the other hand, VMware is a proprietary, commercial product that can be used as either a bare-metal (e.g. ESXi) or hosted hypervisor. Managed through vCenter, VMware offers various tiers and features tailored to your organization’s needs, such as advanced monitoring, disaster recovery, and automation. It offers native features for high availability, disaster recovery (DR), and fault tolerance within the vSphere suite, providing easier configuration and robust options for enterprise users. The mature resource management tools can make it a costlier option, but it dominates in enterprise environments with strict SLAs, high availability, and where premium support is required. It’s ideal for organizations that need robust management features and established vendor support.
The key difference between the KVM Hypervisor and VMware is that KVM is an open-source hypervisor integrated into the Linux kernel, whereas VMware is a proprietary platform. KVM is a cost-effective, open-source solution best suited for Linux environments and organizations favoring open-source stacks. VMware provides a commercial virtualization suite optimized for enterprise environments that require premium support and ease of management.
Below is a table that highlights the key differences between KVM Virtualization vs VMware.
| Feature | KVM Virtualization | VMware |
|---|---|---|
| Licensing | Open-source | Proprietary |
| Platform | Linux-based | Windows, Linux, etc. |
| Hypervisor Type | Type-1 (Bare-metal) | Type-1 (Bare-metal) or Type-2 (Hosted) |
| Supported OS | Linux, Windows, and others | Linux, Windows, and others |
| Graphical Management Tools | oVirt built on top of libvirt, Proxmox, Virtual Machine Manager, Kimchi, Open QRM, and GNOME Boxes for managing libvirt guests | VMware vSphere, vCenter |
| Cost | No licensing fees | Licensing fees |
| Performance | High performance due to direct hardware access | Excellent performance, but may incur overhead due to proprietary nature |
| Scalability | Highly scalable, especially in cloud environments | Scalable |
| Support & Community | Large open-source community; commercial support from third-party vendors like Red Hat or Canonical | Dedicated commercial support from VMware |
| Storage | Software-defined storage support via Lightbits Labs, Ceph, GlusterFS | VMware vSAN, various storage integrations, including Lightbits Labs |
| Ease of Use | Command-line focused | User-friendly GUI |
| Security | Strong security due to Linux kernel integration | Strong security features, including VM isolation |
VMware vs KVM: How to Choose?
Some organizations don’t. It’s possible to use both VMware and KVM as part of a hybrid virtualization environment. For example, you might choose VMware for certain workloads or legacy applications, while KVM could be used for other, more modern, or open-source-based workloads. In this case, both hypervisors would operate in parallel, potentially managed through separate management tools (e.g., VMware vCenter for VMware environments and OpenStack for KVM environments).
If you are making a choice, choosing between VMware and KVM depends on several factors, including your budget, technical requirements, and the scale of your virtualization environment. VMware is ideal if you’re looking for enterprise-grade features, support, and ease of use, and KVM if you want a cost-effective, flexible, open-source solution with full control over your infrastructure.
If you’re looking to deploy a cloud infrastructure, KVM is often preferred due to its integration with OpenStack, OpenShift, and other cloud platforms. VMware cloud solutions, like VMware Cloud Foundation, are proprietary and locked into VMware’s ecosystem. KVM offers greater flexibility and control, especially in environments where you want full transparency and customization of your virtualization setup. It integrates seamlessly with other open-source tools and can be customized to meet specific needs. If your budget is a concern, KVM is an attractive option since it is open-source and free to use, whereas VMware requires purchasing licenses for its products, which can be expensive, especially for large environments.
A KVM-based virtualization platform like Red Hat® OpenShift® Virtualization provides the assurance of comprehensive security features and reliability, as its source code is continuously refined and enhanced by a global community of experienced open-source contributors. As you virtualize traditional applications and establish a foundation for cloud-native and container-based workloads with KVM, you gain from a constantly evolving platform enriched by the collective expertise and advancements of the open-source community. Visit the Red Hat OpenShift Virtualization learning hub to learn more.
KVM and VMware – and Software-Defined Storage
Lightbits high-performance, software-defined elastic block storage seamlessly integrates with many virtualized environments–KVM, VMware, and Azure VMware Solution.
Lightbits for Azure VMware Solution
As the first NVMe® over TCP (NVMe/TCP) storage certified by VMware for Azure, Lightbits delivers enterprise-class external block storage for virtualized workloads running on Azure VMware Solution (AVS). With its high performance and scalability, Lightbits is the ideal data platform for migrating virtualized SQL and NoSQL database workloads to Azure.
Lightbits for VMware
For on-premises deployments, Lightbits is fully certified for VMware ESXi 7.0U3 with in-box NVMe/TCP support. Lightbits allows VMware users to leverage standard Ethernet TCP/IP networks to deploy high-performance, highly available storage that performs like local flash. Furthermore, Lightbits storage solution seamlessly integrates with vCenter, allowing virtualized applications to easily consume and manage high-performance feature-rich NVMe storage. Learn more about Lightbits block storage for VMware.
Lightbits for KVM Virtualization
Lightbits is a simpler block storage solution for KVM-based virtualization that integrates seamlessly with KVM environments, allowing storage resources to be pooled and accessed by multiple VMs without being tied to specific physical devices. The flexible provisioning capabilities of Lightbits storage means that KVM can quickly allocate and deallocate storage based on the needs of VMs, improving efficiency and reducing downtime during storage adjustments. Additionally, Lightbits block storage is dynamically scalable; as workloads grow, storage can be easily expanded by adding more nodes without disrupting existing services. This flexibility is particularly important in KVM environments, which often need to handle varying loads and resource demands.
At Lightbits, we believe in the power of open source. That’s why we’ve developed an open-source Container Storage Interface (CSI) plugin that integrates seamlessly with OpenShift Virtualization. This plugin allows you to easily provision and manage high-performance persistent storage for your VMs, making deployment and scaling a breeze. With our CSI plugin, you can leverage the full power of Lightbits storage within your cloud environment, ensuring that your virtualized workloads have access to the performance and features they need.
To learn more about Lightbits with KVM-based virtualization, read the blog “Kernel-Based Virtualization: A Beginners’ Guide to SDS with KVM.”
Ready to supercharge your virtualization environment with Lightbits? Contact us today for a personalized demo and see the difference for yourself!
1 Wikipedia, “Kernel-based Virtual Machine,” https://en.wikipedia.org/wiki/Kernel-based_Virtual_Machine
