OSI-licensed open source
A virtual server is a machine emulated by software, running on a hypervisor or container manager so many isolated servers share one host. Open-source options range from low-level emulators (QEMU) and microVM engines (Firecracker) to full management platforms (Proxmox VE, Incus) and private-cloud orchestrators (OpenNebula, Apache CloudStack).
This page is for sysadmins and developers building a homelab, private cloud or hosting platform. Licences were read from repositories or licence files.
Tools, licences and pricing checked against vendor and repository pages on November 7, 2026.
| Tool | Best for | Pricing | Licence |
|---|---|---|---|
| Proxmox VE | Self-hosted VMs and containers with a web UI | Free, open source; paid support subscriptions, see vendor pricing | AGPL-3.0 |
| libvirt | Scripting and managing KVM hosts | Free, open source | LGPL-2.1 |
| QEMU | Core VM engine | Free, open source | GPL-2.0 |
| Incus | System containers and VMs via one tool | Free, open source | Apache-2.0 |
| OpenNebula | Private cloud management | Free, open source; enterprise subscriptions, see vendor pricing | Apache-2.0 |
| Apache CloudStack | IaaS for hosting providers | Free, open source | Apache-2.0 |
| Firecracker | Fast-starting isolated microVMs | Free, open source | Apache-2.0 |
Best for: Self-hosted VMs and containers with a web UI · Free, open source; paid support subscriptions, see vendor pricing
Open-source virtualization platform combining KVM virtual machines and LXC containers with a web interface, clustering and storage integration.
Best for: Scripting and managing KVM hosts · Free, open source
Open-source virtualization API and daemon supporting KVM, QEMU, Xen and others.
Best for: Core VM engine · Free, open source
Open-source machine emulator and virtualizer that runs VMs, with KVM acceleration on Linux.
Best for: System containers and VMs via one tool · Free, open source
Modern system container and virtual machine manager with a REST API and CLI, forked from LXD.
Best for: Private cloud management · Free, open source; enterprise subscriptions, see vendor pricing
Open-source cloud and virtualization management platform for private and hybrid clouds.
Best for: IaaS for hosting providers · Free, open source
Apache project providing infrastructure-as-a-service orchestration for large virtual machine deployments.
Best for: Fast-starting isolated microVMs · Free, open source
Open-source virtual machine monitor from AWS for lightweight microVMs used in serverless and container workloads.
One email a week with the tools, launches and releases added to TechLogHub. Unsubscribe in one click.
One email a week: new and trending developer tools, fresh comparisons, and what shipped. Unsubscribe in one click.
| If you need… | Start with |
|---|---|
| Web UI for VMs and containers | Proxmox VE |
| Scripting KVM hosts | libvirt |
| System containers and VMs | Incus |
| Private cloud | OpenNebula |
| Hosting provider IaaS | Apache CloudStack |
| MicroVMs for serverless | Firecracker |
Quick answers to common questions
Software that lets multiple virtual machines share one physical host.
VMs give stronger isolation and a full OS; containers are lighter.
The software is free and open source; paid subscriptions provide support and stable repositories.
OpenStack is also open source and widely used, but is not covered here.
A minimal virtual machine, such as Firecracker, designed to boot fast with a small footprint.
List it on TechLogHub and we'll review it for this guide.
