Virtualization

KVM vs. VMware

How virtualization works

A hypervisor provides the foundation for your virtualization platform, and there are many choices from traditional vendors to open source alternatives. VMware is a popular choice for virtualization, and offers the ESXi hypervisor and vSphere virtualization platform. Kernel-based Virtual Machine (KVM) is an open source option and is part of Linux®.


VMware vSphere platform

VMware offers the ESXi hypervisor and vSphere virtualization platform. VMware ESXi is a bare-metal hypervisor that installs directly onto a physical server and helps you to consolidate your hardware. VMware’s virtualization technologies allow you to create and provision virtual machines (VMs) so you can modernize your infrastructure to deliver and manage new and legacy applications.

Choosing VMware vSphere means you will need to manage your VMs using VMware’s control stack, and there are several license entitlement levels available.


KVM hypervisor

KVM is an open source virtualization technology that changes the Linux kernel into a hypervisor that can be used for virtualization and is an alternative to proprietary virtualization technologies, such as those offered by VMware.

Migrating to a KVM-based virtualization platform means being able to inspect, modify, and enhance the source code behind your hypervisor. Having access to the source code opens the door to innovation, allowing you to virtualize traditional workloads and applications, and also build a foundation for cloud-native and container-based workloads. And because KVM is built into the Linux kernel, it’s easy to use and deploy.


How to choose the right hypervisor

One of the most important areas to consider is how the hypervisor’s performance will impact your infrastructure. KVM and ESXi are both type 1 hypervisors, which means they should outperform a type 2 hypervisor.

ESXi generally requires more time to create and start a server than KVM. ESXi also has slower performance when running servers, although this difference may be insignificant for typical loads. In terms of speed, KVM runs applications at near-native speeds, faster than other industry hypervisors, according to the SPECvirt_sc2013 benchmark.

Hypervisors use different methods to communicate with the physical hardware of the host. ESXi uses VMware’s management platform, which means you will need to use other products in VMware’s control stack. This can also increase your hardware requirements.

You won’t have the same restrictions with KVM because it is open source and can be integrated with your existing infrastructure and with many different Linux and Windows platforms.

Cost is a key differentiator between KVM and the VMware virtualization solutions. KVM is distributed as part of many open source operating systems, so there isn’t an additional cost. With VMware, you will need to purchase licenses for various products and will be locked into an enterprise license agreement (ELA). Although an ELA may save you budget up front, it can increase your costs over time with incremental gains in capacity and functionality in return. Overall, KVM has a lower total cost of ownership.

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

VMware offers a scalable virtualization platform, however it’s important to consider how adding additional hosts or VMs might impact an ELA. vSphere offers a maximum of 12TB of RAM per host with a maximum of 64 hosts per cluster. vSphere includes several application programming interfaces (APIs) that can be used to make management of your VMs easier.

As part of the Linux kernel, KVM scales to match the demand load if the number of guest machines and requests increases. With KVM, the most demanding application workloads can be virtualized, and it is the basis for many enterprise virtualization setups, such as data centers and private clouds.

KVM is also interoperable with your existing infrastructure and gives you access to the source code, which means it is easy to integrate and scale however you need.

With VMware, you will get enterprise-level support as part of your ELA. With KVM, you will need to rely on support from the open source community and your own IT organization, or a supported vendor like Red Hat.


Advantages of KVM over VMware vSphere

VMware offers a well-established, stable hypervisor with excellent performance and features. But proprietary virtualization can keep you from having the resources to invest in clouds, containers, and automation. By removing vendor lock-in, you give yourself the freedom, flexibility, and resources to build the foundation for a cloud-native and containerized future.

KVM is production-ready for enterprise workloads with the features you need to support your physical and virtual infrastructure, at a lower operating cost. Choosing a virtualization option based on KVM has many advantages over other solutions, like VMware vSphere.

KVM has:

  • Lower total cost of ownership, freeing up operating budget to explore modern, innovative technologies.
  • No vendor lock-in. Don’t pay for products you aren’t using or restrict your software choices.
  • Cross-platform interoperability: KVM performs on Linux and Windows platforms so you get more out of your existing infrastructure investments.
  • The simplicity of a single virtualization platform to create, start, stop, pause, migrate, and template hundreds of VMs on hundreds of other hardware or software.
  • Excellent performance: Apps run faster on KVM compared with other hypervisors.
  • The open source advantage: Access the source code and get the flexibility to integrate with anything.
  • Existing features of the Linux operating system:

Why choose Red Hat and KVM for enterprise virtualization

When you choose Red Hat® Virtualization you are choosing KVM. Red Hat Virtualization is a complete infrastructure solution for virtualized servers and technical workstations. Built on the powerful Red Hat Enterprise Linux® platform and KVM, Red Hat Virtualization provides ease of use, agility, and security for virtualized, resource-intensive workloads. It helps organizations optimize their IT infrastructure with better performance, competitive pricing, and a trusted Red Hat environment.

Red Hat’s fast and cost-effective virtualization helps you overcome today’s challenges while building a foundation for future technologies. Current scale-up virtualization solutions provided by vendors such as VMware are costly and provide no path for the organization that desires to move to support cloud-native apps running in a hybrid cloud. Getting away from proprietary virtualization is the first step in moving towards a hybrid cloud environment.

Red Hat Virtualization includes sVirt and Security-Enhanced Linux (SELinux), technologies in Red Hat Enterprise Linux that were specifically developed to detect and prevent complex security threats present in today’s IT environment.

With Red Hat Virtualization, you get all of the benefits of an open source hypervisor, with enterprise-grade technical support, updates, and patches so you can keep your environment up to date and running at all times. Open and RESTful APIs and certification for Microsoft Windows provides cross-platform interoperability. Provided API and software development kits (SDKs) help to extend and support our solution to your existing and preferred management tools.

We can help you easily migrate from VMware or another vendor to Red Hat Virtualization.

What you need to start using KVM

Red Hat Enterprise Linux

Do you have legacy apps that you want to virtualize? Or maybe you’d like to pilot a new app in a low-risk environment. You can configure Red Hat Enterprise Linux as a basic hypervisor for running up to 4 isolated VMs on a single host.

Red Hat Virtualization

This is all you need. Really. Install it on anything—from bare-metal hardware to open source or proprietary systems—and start deploying virtual machines by the dozens or hundreds with an advanced hypervisor that can handle it and a management platform that makes it easy.


There's a lot more to do with virtualization