KVM’s & Hypervisors

Let’s Start With a Simple Question — What is a Hypervisor?

Imagine you have one powerful computer but you want to run five different computers inside it. A hypervisor is the software that makes that magic happen. It creates and manages virtual machines — essentially fake computers running inside your real one.

Example : Think of it like an apartment building. You have one big building (your physical server) and the hypervisor is the landlord dividing it into separate flats (virtual machines). Each tenant (VM) gets their own space, their own resources, and has no idea the other tenants exist.

Type 1 Hypervisor — The Landlord Who Lives in the Building

A Type 1 hypervisor runs directly on the physical hardware. There’s no operating system underneath it — it IS the operating system. It boots up, takes full control of the hardware, and then creates virtual machines on top of it.

This makes it incredibly fast and efficient because there’s no middleman between the hypervisor and the hardware.

Example : VMware ESXi , Microsoft Hyper-V, Proxmox and KVM

Think of it like this: The landlord has a master key, lives in the building full time, controls everything directly, and is deeply embedded in how the building operates. Nobody gets in or out without going through them first.

Type 1 is what you’ll find in enterprise data centres and serious homelabs. It’s built for performance, stability and running workloads 24/7.

Type 2 Hypervisor — The Landlord Who Commutes

A Type 2 hypervisor runs on top of a regular operating system. So you have Windows or Linux running normally, and then you install the hypervisor as just another application on top of it.

The downside? Every time a VM needs hardware resources it has to go through the host OS first — adding latency and overhead. It’s less efficient but much easier to set up and great for desktop use or testing.

Example : VMware Workstation, Virtual Box and Parallels (MAC)

Think of it like this: The landlord works a day job elsewhere, drives in when needed, and has to go through the building manager (the host OS) before doing anything. It works fine, but there’s an extra step involved every time.

So Where Does KVM Fit In?

KVM — Kernel-based Virtual Machine — is where things get really interesting and where most people get confused.

KVM is built directly into the Linux kernel. The moment you enable KVM on a Linux machine, the Linux kernel itself becomes a hypervisor. You’re not adding a separate layer on top — Linux transforms into the hypervisor while still functioning as a normal OS.

This technically makes KVM a Type 1 hypervisor because it operates at the kernel level with direct hardware access. But it feels like a Type 2 because you’re still running a full Linux desktop or server underneath.

Think of it like this: Imagine the landlord went and got a law degree while still living in the building. They’re now simultaneously a resident AND have legal authority over the entire property. They didn’t change where they live — they just became more powerful.

KVM gives you near bare-metal performance while still letting you use Linux normally. It’s why Proxmox, which is built on KVM, is such a popular homelab platform — you get Type 1 performance with a much friendlier setup experience.