Proxmox is an open source virtualisation server I use in my homelab.

From the website:

Proxmox VE is an open-source server management platform for your enterprise virtualisation. It tightly integrates KVM hypervisor and LXC, software-defined storage, and networking functionality on a single platform. With the integrated web-based user interface you can easily manage VMs and containers, highly available clusters, or the integrated disaster recovery tools with ease.

It has a fine web interface which makes configuring and using Proxmox very easy. I don’t want to spend hours configuring and fighting or working around the (artificial) limitations of tools. It just enables me to test and tinker with software, it lowers barriers.

Since Proxmox is based on Linux it is not as demanding as VMware ESXi regarding hardware. Compared to the also “free” VMware ESXi you get a much better working web interface and even clustering and high availability features. Leveraging KVM and LXC means I won’t be restricted to Proxmox if I want to move away.

To me Proxmox seems to have al the right features for a homelab virtualisation environment: low price (free), support for consumer / entry level hardware, flexibility and ease of use.