Following the boat-rocking acquisition acquisition of VMware by Broadcom at the end of 2023, uncertainty and skepticism has been looming among VMware customers as the changes were fast and drastic, impacting everyone in one way or another. While VMware still remains the virtualization leader and isn’t going anywhere (especially for large customers), a number of smaller organizations have been poking around to find whether realistic alternatives exist.
Microsoft Hyper-V is an obvious one but it isn’t excluded that they went the same route at some point with increased license prices for consolidated bundles of software (even if you only want the basics). As a result and in this case, Open-source software is the obvious and safest choice.
There are a few Open-Source hypervisors like Xen and Proxmox but KVM (Kernel-based Virtual Machine) remains the most widely deployed solution out there. All are powerful hypervisors, but Proxmox isn’t exactly tailored for large and scalable environments and Xen is backed by Citrix with paid enterprise features. In the end, we chose KVM to put against VMware vSphere, they differ significantly in their features, management solutions, user-friendliness, licensing models, and more. Understanding these differences is crucial for businesses looking to adopt virtualization technology. In this article, we’ll explore the main disparities between VMware vSphere and KVM.
Hypervisor Features:
VMware vSphere:
- Maturity and Stability: VMware vSphere is a mature and stable virtualization platform trusted by enterprises worldwide. It offers robust features for managing virtualized environments efficiently
- Advanced Management Tools: vSphere provides a comprehensive suite of management tools, the main ones being vCenter Server and the Aria suite of products
- High Availability and Fault Tolerance: It supports features like High Availability (HA) and Fault Tolerance (FT), ensuring minimal downtime and data loss in case of hardware failures
- Resource Management: vSphere offers advanced resource management features such as Distributed Resource Scheduler (DRS) and Storage DRS, optimizing resource utilization across the virtual infrastructure. Along with this, although less used, is also DPM (Distributed Power Management) to optimize electricity consumption by powering down hosts when possible
KVM:
- Open Source: KVM is an open-source hypervisor integrated into the Linux kernel, making it freely available and highly customizable. Finding the right management tools can be challenging when a number of open source or commercial solutions are available
- Performance: KVM is known for its high-performance virtualization capabilities, leveraging hardware virtualization extensions (Intel VT-x and AMD-V)
- Container Support: KVM supports both virtual machines and containers, providing flexibility for different workload types
- Live Migration: Like vSphere, KVM supports live migration, allowing seamless movement of virtual machines between physical hosts without disrupting services
Management Solutions:
VMware vSphere:
- vCenter Server: The central management solution for vSphere environments, offering features like VM provisioning, performance monitoring, and automated resource management
- vSphere Web Client: A web-based interface for managing vSphere environments, providing an intuitive user experience
- PowerCLI: A PowerShell module allowing you to interact with most VMware products
- Aria Suite: An array of products with their own management panes where you get access to all the aspects of your SDDC
KVM:
- Libvirt: Libvirt is a toolkit used for managing different virtualization technologies, including KVM. It provides APIs for managing virtual machines and storage, as well as command-line tools for administration
- oVirt: An open-source virtualization management platform built on top of KVM and Libvirt, offering features like VM lifecycle management, resource allocation, and high availability.
- Virsh, virt-install, virt-viewer : Command line tools to manage virtual machines
User-Friendliness:
VMware vSphere:
- Intuitive Interface: vSphere’s web-based interface is user-friendly and well-designed, making it easy for administrators to manage virtualized environments. Convenient UI for teams that need access to vCenter for basic tasks but don’t have or need the proficiency of the CLI
- Comprehensive Documentation: VMware offers extensive documentation and training resources, helping users get up to speed with vSphere quickly
KVM:
- Steep Learning Curve: KVM’s management tools may have a steeper learning curve, especially for users unfamiliar with Linux and command-line interfaces. Technical specifics are not obfuscated behind a nice UI like vSphere (which arguably is a good thing to learn the product better)
- Community Support: KVM benefits from a vibrant open-source community, providing forums, wikis, and tutorials to assist users in overcoming challenges
Licensing:
VMware vSphere:
- Proprietary Licensing: vSphere is a proprietary solution owned by Broadcom with 2 main subscription based licensing models (VCF and VVF). It no longer offers granular feature sets as customers now have to purchase one of the available bundles. Support comes through an active subscription and is available via VMware’s support processes. Some larger customers pay for a VMware Technical Account Manager (TAM) which is their dedicated point of contact to improve speed of support requests and tailoring the product to their needs
KVM:
- Open Source: KVM is open source and available under the GNU General Public License (GPL). There are no licensing fees associated with KVM itself, although additional management tools or support services may incur costs. By being Open-Source, KVM cannot be subject to earthquake-like changes like Broadcom did for VMware, leaving more than a few customers frustrated and worried about the future of their SDDC
Hardware Support:
VMware vSphere
Hardware support is actually one of the gems of the vSphere Hypervisor. VMware maintains a comprehensive hardware compatibility list (HCL), ensuring broad support for various hardware components. You can easily find which vSphere version supports which hardware product along with compatible driver and firmware versions. VMware also has a list of ready-made server configurations for VSAN called VSAN Ready Nodes that make sizing and designing easier for the customers.
KVM:
As part of the Linux kernel, KVM benefits from broad hardware support. However, users should verify compatibility, especially for specialized hardware and features like nested virtualization. While ensuring “supported” hardware can be less of an issue due to the fact that there is no vendor support like VMware, choosing the right components and optimizing server configuration will prove more challenging than with vSphere.
Additional Comparison Points:
- Ecosystem Integration: VMware vSphere has a vast ecosystem of third-party vendors offering complementary products and integrations. KVM, being open source, also benefits from community-developed integrations and extensions but support will depend on the maturity and the backers of the project
- Scalability: Both vSphere and KVM are highly scalable, supporting large-scale virtualization deployments. However, vSphere’s advanced features like DRS and Storage DRS may offer more granular control over scalability
- Vendor Support: VMware offers comprehensive vendor support with service-level agreements (SLAs) and dedicated support channels. While KVM relies on community support, there are also commercial vendors offering enterprise-grade support for KVM deployments
Conclusion
In conclusion, both VMware vSphere and KVM are powerful hypervisors with distinct advantages and use cases. VMware vSphere is well-suited for enterprises seeking a mature, feature-rich virtualization platform with extensive management capabilities and vendor support. On the other hand, KVM offers the flexibility and cost-effectiveness of an open-source solution, making it ideal for organizations with Linux expertise or those looking for a customizable virtualization platform.
Ultimately, the choice between vSphere and KVM depends on your specific business requirements, budget, and technical expertise. It is without a doubt that the popularity of Open-Source hypervisors like KVM will grow significantly in the near future as the uncertainty around the Broadcom acquisition is making many organizations re-evaluate their needs and options. Time will tell.
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