What is a Hypervisor?

A hypervisor, also known as a virtual machine manager, is a type of software that allows you to create and manage virtual machines.

Hypervisors were invented in the 1960s by IBM, originally intended to be used in IBM’s mainframe computers. But as the world of cloud computing took off, more companies such as VMware, Microsoft and Virtualbox began producing hypervisor products. Expanding offerings for both home and enterprise use.

The virtual machines that a hypervisor creates and manages are also known as virtual servers or virtual desktops.

On the front-end, Virtual machines are a lot like a regular computer. They operate the same as a normal computer. But the back-end of a virtual machine is different to a regular computer.

A regular computer has hardware supporting it on a 1-to-1 ratio, it typically has a CPU, RAM, hard disc etc.. all entirely dedicated to supporting it. Whereas virtual machines are simulated computers allowing for multiple of them to be hosted by one set of hardware – the host computer.

For virtual machines to be created and managed,  hypervisor software has to be installed and connected to the hardware.

Hypervisors play the crucial role of:

1 –  Virtualizing hardware resources and components of the “host computer” so that virtual machines can be supported by the hardware.

2 –  Depending on the quality of the hardware and the hypervisor, there are a limited number of virtual machines that can be created on a host computer. The process of determining and creating the number of available virtual machines is also administered by a hypervisor.

3 – The hypervisor is responsible for isolating all virtual machines on a single host computer so that any changes to or usage of the virtual machines does not affect each other or the host hardware itself.

How Exactly Do Virtual Computers Work?

To understand how virtual machines work and why they are useful, imagine your computer has the Windows 10 OS. But, you are a Computer Programmer that recently completed a new software prototype for Windows 8, Mac OS X, and even Linux.

Testing your software on computers that are used by people such as you or your friends, might be risky and expensive, as there are potentially unforeseen changes that can be caused by your software.

To solve this, you can simply install hypervisor software so you can create three virtual machines.

One with Windows 8, another with Mac OS X, and the last one with Ubuntu. You would then be able to use these virtual machines as if they were three separate computers in addition to your Windows 10 desktop. They would all be accessible through your Windows 10 computer.

This use of virtual machines and hypervisors is called desktop virtualization. But it does not only stop at testing new software, people also use virtual machines to operate old software that is no longer supported by current operating systems.

 Here are two other uses of virtual machines and hypervisors:

1 – Data replication

Hypervisors are used for data cloning and replication by data analysts and firms dealing with organizing and collecting data.

2 – Consolidating servers

Hypervisors enable server consolidation due to their downloadable enhancements. Allowing servers, including those based on different operating systems, to be consolidated.

Types of Hypervisors

There are different types of hypervisors, namely Type-1 and Type-2:

Type-1: A type-1 hypervisor is hosted directly on the hardware of a computer.  This type of hypervisor takes precedence over the operating system of the host computer. This setup makes type-1 hypervisors extremely fast, executing applications and input much faster than type-2 hypervisors.

Type-2: A type-2 hypervisor runs as an application on top of an operating system installed on the host computer. These hypervisors are much less efficient compared to their type-1 counterparts due to having the same access to the host computers hardware as any regular software application installed on the host computer.

Here Are a Few Examples of Type 1 and Type 2 Hypervisors

Type 1 Examples:  

• VMware ESXi: VMware ESXi is a hypervisor for enterprise clients through which they can manage virtual computers. The hypervisor is produced by VMware and is the best option for organizations seeking efficient architecture.
• VSphere: This is a server virtualization offering that includes the VMware ESXi and the vCenter Server which can be used to manage vSphere setups.
• Hyper-V: This hypervisor is produced by Microsoft and is compatible with x86 to x64 systems with Windows operating systems beginning from Windows 8.
• KVM: KVM is an open-source hypervisor linked to Red Hat. The KVM hypervisor is the core of all popular virtual distributions of OpenStack and Linux.

Open-source hypervisors are hypervisors which are built on free and crowd-sourced code. Allowing the hypervisor product to be free if not relatively cheaper.

They are also more frequently updated. While these hypervisors are typically your best option, it is hard to receive professional assistance with problems and troubleshooting for such hypervisors as there is no single organization to hold accountable for customer support.

However, forums and various other online groups and communities exist around most open-source hypervisors.  These communities are dedicated to helping users navigate and troubleshoot issues.

• Citrix XenServer: Also known as the Citrix Hypervisor, it is an open-source hypervisor that supports Linux and Windows operating systems. This hypervisor is a product of the Xen open source project.A non-profit initiative supported by AWS, Intel, Alibaba Cloud, AMD, and Huawei, among many other global tech companies.

Type 2 Examples:

• VMware workstation: This hypervisor works for Linux and Windows operating systems. The pro version allows a single computer to operate multiple operating systems for desktop simulation.

• VirtualBox: Is also another desktop simulation hypervisor for enterprise and home use. The hypervisor is open-source and operates on Windows, Linux, Macintosh and Solaris hosts. It can support very old versions of all the above mentioned operating systems.

• VMware Workstation Player: A VMware hypervisor that allows a single computer to run only a second operating system. It runs with the following host operating systems and all their successor versions: Ubuntu 14.04, Red Hat Enterprise Linux 6,CentOS 6.0,Oracle Linux 6.0, openSUSE Leap 42.2,SUSE Linux 12.

• VMware fusion (MAC OS 10): Allows Mac users to operate almost any other guest operating systems on a computer, with over a hundred options. The VMWare fusion hypervisor is not open sourced and it is produced by VMware.