What Is Virtualization? Hypervisors, VMs and the VMware Exit

Updated: October 2026

That server in the back room is probably running six other computers you can't see. Virtualization is the reason, and it's also why a licensing change at one vendor turned into a migration project for IT teams from small offices to the Fortune 500. Here's how it works, which kind of hypervisor fits which job, and how to pick one now that the old default got expensive.

What Is Virtualization?

Virtualization is software that lets one physical computer behave like many. A layer called a hypervisor sits between the hardware and the operating systems, and hands each virtual machine (VM) its own slice of CPU, memory, storage and network. Each VM thinks it has a whole computer to itself.

The hypervisor is the traffic cop. It decides which VM gets the CPU next, keeps their memory apart, and stops one crashing VM from taking the others down. That isolation is what makes it safe to run a file server, a domain controller and a line-of-business app on the same box.

Virtualization in cloud computing is the same idea at a bigger scale. Every VM you rent from AWS, Azure or Google Cloud runs on a hypervisor in someone else's data center. The cloud didn't replace virtualization. It's built on it.

Type 1 vs Type 2 Hypervisors

There are two kinds of hypervisor, and the difference is what sits underneath them.

A type 1 hypervisor runs directly on the hardware, with no operating system below it. That's why it's called bare metal. VMware ESXi, Microsoft Hyper-V, Proxmox VE (built on Linux KVM), Nutanix AHV and XCP-ng are all type 1. This is what runs production servers.

A type 2 hypervisor is an app you install on a normal operating system, like VirtualBox, VMware Workstation or Parallels on a Mac. Every VM has to go through the host OS to reach the hardware, which costs some speed. It's fine for testing, training and running a second OS on a laptop.

The rule of thumb: type 1 runs the business, type 2 runs the lab.

One setting ties both together. Modern Intel and AMD CPUs ship with hardware virtualization support (Intel VT-x or AMD-V), and it has to be switched on in the BIOS or UEFI for a hypervisor to work well. If a VM refuses to start on a new machine, that switch is the first thing to check. Here's how to enable virtualization in BIOS on each major vendor's firmware.

What IT Teams Virtualize

Server virtualization is where the biggest savings sit. Instead of one application per physical server, a single host runs a dozen VMs. That means fewer boxes to buy, power and cool. It also brings three things a physical server can't do: snapshots before a risky change, live migration of a running VM to another host during maintenance, and restoring a whole server from a VM backup in minutes rather than rebuilding it.

Desktop virtualization (VDI) runs user desktops as VMs in the data center, so a thin client or an old laptop can reach a full Windows desktop. Storage virtualization pools disks from several machines into one logical store. Network virtualization does the same for switches and firewalls, carving virtual networks out of shared hardware.

Put together, those layers describe a modern server room. Our guide to IT infrastructure management covers how they're run day to day.

Virtual Machines vs Containers

A VM carries a complete operating system: its own kernel, its own drivers, its own updates to install. A container shares the host's kernel and packages only the app and the libraries it needs. That makes containers smaller and faster to start, but every container on a host depends on the same kernel.

They solve different problems. VMs isolate whole systems, which suits a Windows server, a legacy app or anything that needs its own OS. Containers package applications, which suits modern software built to scale out. Plenty of shops run containers inside VMs and get both.

This r/sysadmin thread asked people what they run, and the most-upvoted reply draws the line in one sentence: Docker, Kubernetes and LXC "are not virtualization. They are containerization."

Why Everyone Is Rethinking VMware

For years, the default answer to "which hypervisor?" was VMware. Then Broadcom bought the company, closing the deal in November 2023, and changed how it sells.

On 11 December 2023, Broadcom announced the end of perpetual licenses and a move to subscription bundles, mainly VMware Cloud Foundation and VMware vSphere Foundation. Customers who had bought VMware outright could keep running it, but new patches and support now came only with a subscription.

The enforcement followed. In May 2025, Broadcom sent cease-and-desist letters to perpetual-license holders whose support had lapsed, telling them to remove patches installed after support ended. Its June 2026 VMware Cloud Foundation terms require customers to file a compliance report every 180 days, or management features get degraded and support is suspended.

That turns every VMware estate into something that can be audited on demand. Our software license audit guide covers how to get ahead of that.

The pain shows up in the details. In this December 2025 thread, one team describes a VMware support renewal going from $43,000 to $99,000. They let it lapse, and their rep then warned of "environment disruptions" if a purchase order didn't arrive that day. The top reply: get legal involved.

Hosting providers took a hit too. Broadcom closed its VMware cloud partner program in January 2026, so providers that ran VMware for their clients lost their path to keep selling it.

VMware still works well, and some teams will stay. The difference is that staying is now a budget decision, not a default.

How to Pick a Hypervisor in 2026

Start with what you already own and what your team already knows. The right hypervisor is usually the one your people can run at 2 a.m.

If you already pay for Windows Server Datacenter, Hyper-V is included, and Datacenter licensing covers unlimited Windows Server VMs on the licensed host. It's mature and familiar to Windows admins. The management tools feel older than VMware's, but the price is hard to argue with.

If your team is comfortable with Linux and budget is the pressure, Proxmox VE is the open-source option. It's free to run, with paid subscriptions for the stable enterprise update channel and support. The one catch to check first: some application vendors only support their software on hypervisors they've certified, and Proxmox isn't always on that list.

If you want compute and storage in one appliance, Nutanix with its AHV hypervisor is the hyperconverged route. If you're staying on VMware, budget for the subscription and the compliance reporting, and put the renewal date on the calendar a year out.

Whichever you pick, test the migration on your smallest host first. In this August 2026 r/ITManagers thread, a team with 150 VMs across four hosts weighs Hyper-V against Proxmox. A small MSP in France replies that it moved every client with servers to Proxmox in 2024, with no problems so far.

Don't forget what sits around the hypervisor. VM backup, monitoring and automation all have to follow you to the new platform. Our Veeam review covers how one backup tool handles Hyper-V and Proxmox.

Automation helps the move too. Tools like Terraform and Ansible can rebuild VMs from code instead of by hand, as our IT automation software guide explains.

Professor Messer's short explainer covers the building blocks in one go: hypervisors, type 1 and type 2, CPU support, VDI and containers.

One Box, Many Machines

Virtualization turns one server into many, and a type 1 hypervisor is what runs the business. The technology hasn't changed much in years. The pricing has, and that makes 2026 a good year to check whether your hypervisor still fits your budget and your team.

For the bigger picture of how the pieces fit, our roundup of IT operations management tools is the next read.