OpenNebula

What Is OpenNebula?

OpenNebula is an open-source platform for running private, hybrid and edge clouds, and it is a different kind of VMware replacement from the usual shortlist. Most alternatives swap one hypervisor for another. OpenNebula sits above hypervisors and manages KVM, LXC containers, Kubernetes clusters and VMware vCenter from one control plane.

The assumption worth challenging is that leaving VMware means choosing a new hypervisor. Often the more useful question is what manages your estate while you leave. A cloud layer that can run VMware and KVM side by side lets you migrate in stages instead of in a single cutover.

The company behind it is OpenNebula Systems S.L., based in Pozuelo de Alarcón near Madrid, registered in 2010 and formerly named C12G Labs. The project itself began as research at Universidad Complutense in 2005, with its first public release in 2008. Ignacio M. Llorente leads the company as CEO.

One disclosure matters. OpenNebula Systems USA, LLC in Burlington, Massachusetts is a subsidiary, set up in 2015, and OpenNebula's own post from then calls it a new subsidiary. The contact page labels Burlington "USA Headquarters" next to a Madrid "EMEA Headquarters", and the US LLC filed the US trademark. GLEIF records no consolidating parent for the Spanish company, so the Spanish S.L. is the top entity.

Funding appears public rather than venture-backed. The company won a €2.1 million H2020 SME Instrument grant in 2019 and coordinates work in the EU IPCEI-CIS programme. We found no equity investors.

In July 2025 the cloud association CISPE asked the EU General Court to annul the European Commission's clearance of Broadcom's VMware acquisition. It cited contract terminations at a few weeks' notice and cost increases it described as sometimes exceeding tenfold. OpenNebula positions itself openly as a VMware alternative.

Key Features

One Control Plane for Mixed Estates

Version 7.0 manages KVM, LXC and VMware vCenter. For a company that cannot move every workload at once, this is the headline feature. You can bring existing vSphere clusters under OpenNebula, deploy new capacity on KVM, and shift workloads over months. It also includes VMware migration tooling.

Compare this with Proxmox, which is a complete hypervisor product, or XCP-ng, which is built on Xen. Those are destinations. OpenNebula is a manager that can also be a destination.

Multi-Tenancy and Federation

Role-based multi-tenancy gives separate teams or customers their own quotas and views. Federation joins multiple sites under one architecture. This design comes from the cloud-provider world, and it suits hosting companies and public-sector consortia better than a three-host office cluster.

Virt8ra is the public example: a sovereign multi-provider cloud that OpenNebula built with IONOS, OVHcloud and Scaleway.

Kubernetes and GPU Workloads

Kubernetes lifecycle management is built in. OpenNebula describes the platform as covering virtual machines, Kubernetes clusters and GPU workloads in hybrid environments, and it markets itself for AI infrastructure as well. If your roadmap includes private AI hosting, GPU support from the same console is a practical advantage.

Automation and Orchestration

OneFlow orchestrates multi-VM services, and OneGate lets a running service instance talk back to the platform. There are REST and XML-RPC APIs, the Sunstone graphical interface, and documented use of Terraform and Ansible. The marketplace offers pre-configured appliances.

For evaluation, the miniONE installer builds a single-server test deployment. Production designs need more: a front-end, storage, network and a decision on high availability.

What Is Enterprise Edition?

Licensing needs a careful reading. The Community Edition is published on GitHub under Apache-2.0. The Enterprise Edition is delivered to subscribers, and OpenNebula's subscription page describes a perpetual licence and a bits-only licence for staging.

OpenNebula calls its software fully open source, while the Wikipedia entry describes the Enterprise Edition as a closed-source licence plus subscription. We could not reconcile those from public material. Ask for the Enterprise Edition licence text before you sign.

Pricing

OpenNebula publishes no prices. The subscription page offers two Enterprise plans and asks you to get in touch for a tailored proposal.

Standard gives 9x5 support (CET, EST), two named accounts, and access to the Enterprise Edition and Enterprise Portal. Premium adds 24x7 support, four named accounts, workarounds and hot fixes, product influence, remote access by ssh, and supervised upgrade assistance. Both include SLA-backed support, unlimited service tickets, and unlimited CPUs, cores and VMs.

That last point is the commercial hook. Pricing is not tied to hardware size, which sidesteps the per-core debates that VMware customers know well. Optional extras include embedded Ubuntu Pro, RHEL or SUSE subscriptions, Ceph and Kubernetes integration support.

The downside is opacity. Without a price list, you cannot compare OpenNebula against Proxmox at €370 per socket or Vates at $1,000 per host without a sales call. Small teams will find that friction annoying.

The Community Edition is free to run for any purpose that Apache-2.0 permits. It comes without a vendor SLA, so production use at scale usually means a subscription.

EU Compliance & Privacy

OpenNebula Systems S.L. is registered in the Madrid commercial register and is subject to Spanish law and GDPR. The platform is self-hosted, so the vendor does not hold your workload data.

OpenNebula Systems holds a Spanish ENS certificate (Esquema Nacional de Seguridad) at category Medium. It was issued on 10 July 2026 by Applus+ and is valid to 10 July 2028. Coverage extends to OpenNebula Systems' support and professional services, not your own deployment. For Spanish public-sector buyers this is a relevant procurement signal.

The US subsidiary is a point for your due diligence rather than a red flag. If your legal team wants to know which entity signs the contract, ask directly. We did not verify ISO 27001 or SOC 2 reports for the company and do not claim them.

Public EU involvement is a strength. OpenNebula took part in the Virt8ra sovereign cloud work and coordinates in IPCEI-CIS, a state-aid programme running from 2024 to 2028.

Who It's Best For

Service providers and hosting companies. If you run multi-tenant infrastructure, OpenNebula's tenant model and federation fit better than a single-site hypervisor.

Organisations with mixed estates. If you need to keep vSphere alive while building a KVM-based replacement, the vCenter integration lets you manage both and migrate in stages.

Public-sector and sovereignty-led buyers. If a Spanish or EU-funded programme matters to procurement, the ENS certificate and EU project record help.

Small teams with three servers. If you just need a hypervisor that runs, choose Proxmox or XCP-ng. OpenNebula is more platform than you need.

Buyers who need public pricing. If budget approval requires a list price, expect a longer path than with competitors.

The Verdict

OpenNebula is the strongest European option when your problem is managing a cloud estate through a VMware exit rather than installing a single hypervisor. Its multi-hypervisor design, federation and Kubernetes support are real strengths. The trade-offs are quote-only pricing, an Edition split that is described inconsistently, a smaller community than Proxmox, and more design work up front. A survey by CloudBolt of 302 North American IT leaders found 86% reducing VMware use and only 4% fully migrated, with moves typically taking 18 to 24 months. That reality suits a tool built for staged moves. See the cloud hosting category and the VMware alternatives page for other routes.

Frequently Asked Questions

Is OpenNebula free and open source?

The Community Edition is free and published on GitHub under Apache-2.0. The Enterprise Edition is delivered to subscribers with support. OpenNebula describes its software as open source, but sources differ on the Enterprise Edition licence terms, so confirm them in your contract.

How much does OpenNebula cost?

Prices are not published. Enterprise subscriptions come in Standard (9x5) and Premium (24x7) plans with unlimited CPUs, cores and VMs, and pricing is by tailored proposal. The Community Edition costs nothing but has no vendor support.

Can OpenNebula replace VMware vSphere?

It can manage KVM and LXC natively and also integrates with VMware vCenter, so you can migrate in stages. The product is a cloud management platform rather than a hypervisor, so plan storage, networking and a front-end design before moving production workloads.

Is OpenNebula a European company?

Yes. The operating company is OpenNebula Systems S.L., registered in Madrid and based in Pozuelo de Alarcón. A US subsidiary, OpenNebula Systems USA, LLC, exists in Massachusetts but is not a parent. We identified EU grant funding but no venture investors.

How does OpenNebula differ from Proxmox?

Proxmox is a single integrated virtualisation product built on KVM and LXC with a built-in web interface. OpenNebula is a cloud management layer that can federate multiple sites, orchestrate Kubernetes and manage VMware, with a more cloud-like tenant model.