Proxmox VE gives you two ways to slice a server: full virtual machines via KVM, and LXC system containers that share the host's kernel. The right choice per workload is usually clear once you know the three questions that decide it: isolation, kernel, and migration. This guide explains how each actually works, compares them on the dimensions that matter operationally, settles the Docker question with Proxmox's own current guidance, and ends with a decision table you can apply per service.