Introduction

Before starting a new articles serie on VMWare, let’s see together how virtualization works. As you probably know, it’s fairly an old technology but it’s still relevant to design a cloud computing solution and it’s important to understand how it works for obvious reasons.

What is virtualization ?

 Virtualization refers to the act of creating a virtual (rather than actual) version of something, including virtual computer hardware platforms, storage devices, applications and computer network resources.

This is feaseable through an Hypervisor which is basically a piece of software that runs above the physical server or host.

There a 2 main types of hypervisor :

1. Bare metal (type 1) : The hypervisor is directly installed on the top of your hypervisor. Examples : VMWare ESXi, Windows HyperV, KVM…
2. Hosted (type 2) : There are a layer of host OS that sits between the physical server and the hypervisor. Examples : VirtualBox, VMWare Workstation

Bare metal Hypervisors are the most used because the main reason is that they are highly secured and they lower the latency.

Hosted are much less used because of their higher latency than a type 1.

Once your Hypervisor is installed, you can start create virtual machines (called VMs.)

A VM is basically a software based computer.They run like a physical computer, they have an operating system and applications and they are completely independent.

So the main advantage of virtualization is that you can run multiple VMs on the same hypervisor which will be able to manage the ressources allocated to them from the physical server.

Moreover, as VMs are independent, you can move one virtual machine from an hypervisor to another one on a completely different physical machine almost instantaneously.

This gives you a lot of flexibility during upgrades for example or even during an host failure !

What are the benefits of virtualization ?

1. Cost saving : as you can run multiple virtual environment on one host you can drastically reduce you cost (electricity, physical servers etc.)
2. Agility and speed : virtualization is easy to manage and it saves you time with deployments.
3. Reduce downtimes : As explained previously, you can easily move your VMs between hypervisors.
4. Great isolation of environments and better security than containers in my opinion.

In the next articles we will continue to discuss about virtualization but we will be focused on VMWare solution.

Sources :

• wikipedia.org
• vmware.com