Virtualisation and container platforms divide physical servers into virtual machines and containers and orchestrate them at scale. Organisations use them to run their own data centres, to consolidate workloads and to build internal platforms for application teams.
Licence terms of proprietary hypervisors and management suites can change when ownership changes, with consequences for cost and support. Managed Kubernetes from a hyperscaler ties you to that provider's networking, identity and storage services, even though Kubernetes itself is open. Open-source components such as KVM, Xen or upstream Kubernetes give you a portable core, but the support contract and the vendor's ownership still matter. The EU Data Act gives customers of data processing services rights to switch providers, yet in practice moving workloads depends on functional equivalence.
In a European option, check whether the core is open source and can be run without the vendor, which components are proprietary, where support engineers are based and under which law they work, and whether the stack runs on bare metal, on European clouds and on your own hardware.