OSI-licensed open source
Server virtualization runs multiple virtual machines on shared hardware. Open-source options cover hypervisors, management layers and full cloud platforms, and have become more attractive to teams reconsidering proprietary hypervisor licensing.
The list includes hypervisors and low-level tooling (QEMU/KVM, Xen, libvirt), complete virtualization platforms (Proxmox VE, Incus, Harvester) and cloud orchestration (OpenNebula, Apache CloudStack). Licences were read from each project's repository this run. It targets sysadmins and platform teams building self-hosted infrastructure.
Tools, licences and pricing checked against vendor and repository pages on November 7, 2026.
| Tool | Best for | Pricing | Licence |
|---|---|---|---|
| Proxmox VE | All-in-one VM and container management with a web UI | Free, open source (self-hosted); paid support subscriptions available | AGPL-3.0-or-later |
| QEMU/KVM | Building blocks for Linux virtualization | Free, open source | GPL-2.0 |
| Xen Project | Type-1 hypervisor deployments | Free, open source | GPL-2.0-only |
| OpenNebula | Private clouds managing VMs and edge | Free, open source | Apache-2.0 |
| Incus | Containers and VMs under one manager | Free, open source | Apache-2.0 |
| Harvester | Kubernetes-native HCI | Free, open source | Apache-2.0 |
| libvirt | Programmatic VM management | Free, open source | LGPL-2.1-or-later |
| Apache CloudStack | Multi-tenant private clouds on virtualization | Free, open source | Apache-2.0 |
Best for: All-in-one VM and container management with a web UI · Free, open source (self-hosted); paid support subscriptions available
Proxmox VE is a virtualization management platform whose manager code is published under AGPL-3 or later per its debian/copyright file.
Best for: Building blocks for Linux virtualization · Free, open source
QEMU is the machine emulator and virtualizer, released under GPL version 2, and commonly used with KVM.
Best for: Type-1 hypervisor deployments · Free, open source
Xen is an open-source hypervisor released under GPL version 2.
Best for: Private clouds managing VMs and edge · Free, open source
OpenNebula is an open-source cloud and edge computing platform; the repo lists Apache-2.0 plus additional licence files.
Best for: Containers and VMs under one manager · Free, open source
Incus is a powerful system container and virtual machine manager under Apache-2.0.
Best for: Kubernetes-native HCI · Free, open source
Harvester is open-source hyperconverged infrastructure software, a Kubernetes-based virtualization and storage platform for bare metal.
Best for: Programmatic VM management · Free, open source
libvirt is a portable C API for managing virtualization technologies including QEMU, KVM and Xen; the library is LGPL 2.1 or later.
Best for: Multi-tenant private clouds on virtualization · Free, open source
Apache CloudStack is an open-source IaaS cloud computing platform.
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| If you need… | Start with |
|---|---|
| Easiest all-in-one with a web UI | Proxmox VE |
| Building blocks | QEMU/KVM, libvirt |
| Type-1 hypervisor | Xen Project |
| Containers and VMs together | Incus |
| Kubernetes-native HCI | Harvester |
| Private cloud | OpenNebula, Apache CloudStack |
Quick answers to common questions
KVM, driven through QEMU, underpins platforms such as Proxmox VE and libvirt-based stacks.
The software is open source; paid subscriptions provide support. Check Proxmox for current pricing.
XCP-ng is a Xen-based platform, but its licence was not verified on a repository page this run, so it is not listed.
Both are mature. KVM is integrated in the Linux kernel; Xen is a standalone type-1 hypervisor.
List it on TechLogHub and we'll review it for this guide.
