The VMware hypervisor ESXi is a bare metal type 1 hypervisor designed to run on a physical server to partition hardware. The previous version, ESX, loaded a Linux kernel as a service console, but the Linux kernel was dropped in version 4.1. ESXi now uses the vmkernel to run hardware, the guest computing systems, and the service console. ESXi also requires either the free vSphere software or a paid subscription vSphere 7 plan. Learn more about KVM vs VMWare and decide what's best for you now.