KVM vs. VMware

A hypervisor provides the foundation for your virtualization platform by pooling computing resources and reallocating them among virtual machines (VMs). There are many options available when choosing a hypervisor—from traditional vendors to open source alternatives. VMware offers the ESXi hypervisor and vSphere virtualization platform, a proprietary bare-metal hypervisor. Kernel-based Virtual Machine (KVM) is an open source hypervisor and runs on Linux® hosts.

Migrate your VMs to a KVM-based solution

KVM is an open source Linux technology that enables the Linux kernel to support virtualized workloads, effectively turning the host system into a hypervisor that can be used as an alternative to proprietary virtualization technologies. KVM is built into the Linux kernel, providing a user-friendly interface and easy deployment options.

Migrating to 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.

Try Red Hat OpenShift Virtualization

VMware offers the ESXi hypervisor and vSphere virtualization platform. VMware ESXi is a proprietary bare-metal hypervisor that installs directly onto a physical server and helps you consolidate your hardware.

The vSphere platform is a suite of virtualization components. It includes vCenter for server and infrastructure management and services like vMotion for live migration and vSAN for shared storage. VMware’s virtualization technologies let you create and provision virtual machines (VMs) so you can modernize your virtual environment to deliver and manage both new and traditional applications.

VMware and KVM-based virtualization platforms such as Red Hat OpenShift Virtualization cater to different sizes of workload, levels of support needed, and pricing considerations. Other virtualization platforms include:

• Hyper-V: Microsoft’s virtualization platform is optimized for Windows environments. It requires Windows Server licensing to run and may not be as compatible with other operating systems.
• Nutanix: Nutanix offers a specialized virtualization solution with features that support scalability and cloud-native development. However, this specialization can introduce a steep learning curve for some users.
• Proxmox VE: This open source server management platform benefits from a large community of contributors, but enterprise-level support is only available as a commercial add-on.   
• Oracle Virtualization: Oracle Virtualization is an enterprise software based on KVM. Oracle also offers the Oracle VirtualBox hypervisor.

Performance

One of the most important considerations is how the hypervisor’s performance will impact your infrastructure and the applications running on top of it. KVM and ESXi are both type 1 hypervisors, which are most common in enterprise datacenters and other server-based environments thanks to their high performance capabilities.

ESXi generally requires more overhead to create a virtual machine than KVM, which has fewer lines of code and more hardware compatibility options.

Integration

Hypervisors use specific methods to interact with the physical hardware of the host system, which depend on the type of hypervisor. Open-source hypervisors like KVM rely on the Linux kernel for direct hardware interaction, leveraging kernel-based drivers to support a wide range of hardware architectures. A driver makes it possible to simulate hardware in a virtual environment. Proprietary hypervisors like VMware ESXi use tightly integrated drivers and hardware certification processes to ensure optimized performance.

Separately, hypervisors also vary in how well they integrate into broader management ecosystems. KVM, for instance, is designed to work seamlessly with the board offering of open-source management tools, providing flexibility for users to build customized management processes and solutions. In contrast, VMware ESXi is tightly integrated with VMware’s management platform, including vCenter, to offer a unified experience for virtualization and operations.

Cost

Cost-effectiveness is a key differentiator between KVM and VMware virtualization solutions. KVM is part of many open source operating systems—KVM was merged into the Linux kernel in 2007, so if you’re using a modern version of Linux, you already have access to KVM. VMware requires you to purchase subscriptions for various VMware products and locks you into an enterprise license agreement (ELA). Although an ELA may save you money up front, it can increase your costs over time with only incremental gains in capacity and functionality in return.

Maturity

Both KVM and ESXi are mature and stable hypervisors that can support enterprise workloads.

Scalability

Both KVM and VMware ESXi are designed to support large-scale virtualization environments, each offering distinct scalability features. KVM, integrated into the Linux kernel, benefits from the kernel’s inherent scalability and supports a wide range of hardware architectures. It can handle large numbers of VMs efficiently, making it suitable for diverse enterprise level workloads. Likewise, VMware ESXi, provides significant scalability for virtual machines. This high level of scalability is advantageous for large enterprises requiring extensive virtualization capabilities. Both hypervisors offer features that cater to different scalability needs, allowing organizations to choose based on their specific requirements.

Security

Strengthening your hypervisor’s security throughout its lifecycle is critical. If an attacker reaches your hypervisor, they’re one step away from all your VMs and their data.

VMware offers security features such as a firewall, infrastructure hardening, compliance monitoring and remediation, distributed lateral security, and confident cyber recovery.

KVM uses a combination of Security-Enhanced Linux (SELinux) and secure virtualization (sVirt) for enhanced VM security and isolation. SELinux establishes security boundaries around VMs. sVirt extends SELinux’s capabilities, allowing mandatory access control (MAC) security to be applied to guest VMs and preventing manual labeling errors.

Support

With VMware, you get enterprise-level support as part of your ELA. With KVM, you’re reliant on support from the open source community, your organization’s IT department, or via enterprise level support from vendors such as Red Hat.

VMware offers a well-established, stable hypervisor with proven performance and advanced feature sets. But proprietary virtualization and vendor lock-in can consume your budget and limit your opportunities to invest in clouds, containers, and emerging technologies such as AI. By removing vendor lock-in with open source technology like KVM, you have the freedom, flexibility, and resources to build the foundation for cloud-native and containerized modernization.

KVM is production ready for enterprise workloads with features that support your physical and virtual infrastructure.

KVM benefits include:

• No vendor lock-in, meaning you won’t pay for products you don’t use or restrict your software choices.
• Cross-platform interoperability. KVM performs on many Linux distributions so you get more out of your existing infrastructure investments.
• The simplicity of a single virtualization platform to migrate, and manage hundreds or thousands of VMs in many other hardware or software environments.
• The open source advantage. Benefit from contributor-vetted code that provides flexibility to integrate with a wide range of systems, tailored to your specific environment and needs.
• Existing features of the Linux operating system:
  • Security features
  • Memory management
  • Process scheduler
  • Device drivers
  • Network stack

KVM is the hypervisor behind Red Hat’s virtualization portfolio, and we continually improve the Linux kernel code with contributions to the KVM community. Get the flexibility and benefits of an open source hypervisor like KVM with the assurance of Red Hat’s enterprise experience and support, security features, and stability. We offer a complete solution to help you migrate VMs now—and run them with confidence.

Red Hat’s trusted products and partner ecosystem come together in one comprehensive virtualization solution. Migrate your virtual machines now to Red Hat OpenShift Virtualization―a modern virtualization platform based on the open source projects KVM and KubeVirt. The included migration toolkit for virtualization provides the tools you need to start migrating in a few simple steps. Use automation to accelerate delivery and for the migration of virtual machines at scale with Red Hat Ansible® Automation Platform–from migration to Day 2 operations. Monitor the security and performance of your VMs from a single console with Red Hat Advanced Cluster Management for Virtualization. With additional support options and partner integrations for storage, backup and disaster recovery, and networking, you can rely on Red Hat to keep your virtual infrastructure running smoothly, with modernization options through cloud-native tooling.

Migrate to a KVM-based solution

Red Hat is here to help you start migrating your virtual infrastructure. Explore the interactive walkthrough to learn how to create a migration plan, use Ansible Automation Platform and the migration toolkit for virtualization to automate the migration process, and start managing your VMs on Red Hat OpenShift Virtualization.

Need help? The Virtualization Migration Assessment offers hands-on support from Red Hat Consulting to provide a clear roadmap and timeline for migrating your VMs.