XCP-ng

XCP-ng is an open source server virtualization platform built on the Xen hypervisor, developed as part of the Vates virtualization stack. It is distributed without feature restrictions, and is managed through Xen Orchestra, a web based interface that handles hosts, virtual machines, backups and migration across an estate.

Unrestricted access to features is the position the project was founded on and it is the reason it exists as a separate distribution. Commercial hypervisors commonly reserve capabilities such as live migration or advanced backup for higher licence tiers, so a small operator ends up paying enterprise rates for a handful of features or doing without them. XCP-ng makes the full feature set available and sells professional support separately for organisations that need it.

Live migration is called out specifically, allowing running virtual machines to move between hosts without interruption, which is the capability that turns a group of servers into something that can be maintained without scheduled downtime. Clustering allows the estate to grow by adding hosts.

Running on a customer's own bare metal is the other stated benefit, giving control over the hardware with no shared tenancy. The project maintains an active community with public forums and documentation, and Vates offers paid professional support for production deployments.