Set Up Virtual Machines Using VirtualBox and vSphere

Understand the Function of a Type 1 Hypervisor 

Type 1 hypervisors, often called native or bare-metal hypervisors, are different from type 2 hypervisors – they are installed directly on physical hardware, without an intermediary operating system. 

With a type 1 hypervisor, the host resources are directly managed by the hypervisor, not the operating system.

This principle becomes clear when you install ESXi (the VMware vSphere hypervisor), which, as you’ll see, completely removes the operating system and any existing data from the host. 

Let’s go back to our tree example and see how a type 1 hypervisor compares to its type 2 counterpart.

With a type 1 hypervisor, the host machine is used to create VMs and can’t do anything else.

This type of hypervisor is used in a completely different context from a type 2 hypervisor, mainly because of its superior performance, which is a result of:

• Direct access to the resources (without going through an operating system).

• All resources being allocated to VMs.

Type 1 hypervisors are used in businesses for many purposes, such as:

• Reducing hardware and maintenance costs.

• Optimizing physical resources.

• Dynamically distributing resource load. 

• Making servers highly available.

• Creating pre-production VMs to test them in a real environment before using them for production.  

Different Type 1 Hypervisors

It’s challenging to compare the various functions across different type 1 hypervisors accurately because they include different features, prices, and license types.

What’s more, it’s quite rare for IT professionals to have to choose between these different solutions, simply because:

• When you arrive in a company, there will probably already be an existing virtualization solution.

• Choices can often be based on factors other than technological criteria. Your company may have contracts with certain suppliers who partner with virtualization providers.

However, it’s good to know the market trends.

It’s difficult to compare them on price as they offer different types of licenses. Still, if you consider equivalent licenses in terms of services, vSphere is the most expensive, followed by Hyper-V for typical business use.

• ESXi replaces the operating system, so there’s no confusion there.

• Hyper-V is a little more complicated as you need to install Windows first and then Hyper-V. You might then think that Hyper-V is application on the operating system and has no control over the host machine’s resources. However, this isn’t true. When you install Hyper-V, the system undergoes significant changes, and your Windows operating system becomes a VM.

• Xen uses the same principle: your main operating system becomes a VM.

• KVM works slightly differently. The KVM module installed on a Linux system modifies the Linux kernel to access hardware resources directly.

So you see, there are several ways of implementing direct access to the host machine’s resources without having to get rid of the operating system as ESXi does completely.

To summarize: the type of hypervisor required for your environment is determined by your use cases. 

 Let’s Recap!

• Type 1 hypervisors, also known as bare-metal hypervisors, are installed directly on physical hardware without an intermediary operating system.

• Type 1 hypervisors have superior performance because they have direct access to the resources, and all are allocated to their VMs.

• Type 1 hypervisors are used for:

  • Reducing hardware and maintenance costs.

  • Optimizing physical resources.

• The most popular type 1 hypervisors are:

  • ESXi

  • Hyper-V

  • KVM

  • Xen

We’ve now covered type 1 hypervisors in enough detail for you to understand how they work and what they are used for. Next, take the quiz to see how much you have learned about virtual machines and type 1 and type 2 hypervisors.  

When you finish, head over to part 2 of the course, where you’ll gain some practical experience setting up a test environment using a type 2 hypervisor!