In the world of IT, server virtualization is a hot topic What is a Hypervisor and Its Types? particularly at the enterprise level. It makes it possible for many operating systems to utilize the same physical resources while running various applications on a single server.
System and network managers can now have a dedicated machine for each service they need to run thanks to virtual machines. This not only cuts down on the number of physical servers needed, but it also speeds up problem-solving.
This article will describe hypervisors, crucial components of the server virtualization process. It will cover what hypervisors are, how they work, and their different types.
How do hypervisors work?
What is a Hypervisor and Its Types? Virtualization is made possible by a critical component of software called a hypervisor. It establishes a virtualization layer to distinguish between the virtual computers and the operating systems they run and the actual hardware elements, such as CPUs, RAM, and other physical resources.
The virtual instances that are running on top of the hypervisor are referred to as the guest virtual machines, while the machine hosting the hypervisor is referred to as the host machine.
In order for guest machines to use the available resources, hypervisors simulate them. Any operating system that starts up on a virtual machine will first believe that it has access to real physical hardware.
Why Employ a Hypervisor?
There is no distinction between real and virtualized environments from the perspective of a VM. Guest machines are unaware that they were generated in a virtual environment by the hypervisor or that they share available processing power.
Companies planning to: will find the hypervisor advantageous because it enables VMs to operate as common computing instances.
- Utilize their computing resources as efficiently as possible: The CPU and memory of a single server running many virtual environments are fully used.
- Improve the mobility of IT: The VMs can be simply moved to different systems and are independent of the host hardware.
Various Hypervisor Types
According to where they are located in the server virtualization framework, there are two different types of hypervisors:
- Type 1 hypervisors, sometimes referred to as native or bare-metal.
- Hosted hypervisors, also referred to as Type 2 hypervisors.
What is a Hypervisor and Its Types? More information on each type is provided in the sections below.
Hypervisor Type 1
A Type 1 hypervisor is a software layer that is put right on top of a physical server’s hardware. It is also known as the bare-metal hypervisor since no additional software is running between the hardware and the hypervisor.
Due to its independence from Windows or any other operating system, this sort of hypervisor offers exceptional performance and stability. Rather, it is a straightforward operating system made for running virtual computers. The hypervisor’s host physical machine is only used for virtualization.
Most type 1 hypervisors are found in business settings.
A physical server that has a bare-metal hypervisor installed boots up and shows some hardware and network information on a screen resembling a command prompt. They consist of the MAC address, the IP address, the RAM size, and the type of CPU.
Below is an example of a VMware ESXi type 1 hypervisor screen when the server powers up.
Benefits and Drawbacks of Type 1 Hypervisor
Type 1 hypervisors lack comprehensive administration tools but have significant performance and security advantages. The benefits and drawbacks of utilizing this kind of hypervisor are listed below.
Benefits
- Mobility for VMs
Virtual machines can be manually or automatically moved between real servers using type 1 hypervisors. This action is based on a VM’s current resource requirements and has no bearing on end users. Management software immediately relocates virtual machines to a functioning server in the event of a hardware breakdown. The process of detection and repair is automatic and seamless.
- Security
Without an intermediate OS layer, type 1 hypervisors have direct access to hardware. The attack surface for possible bad actors is greatly reduced by this direct connection.
- Overuse of Resources
You can provide your virtual machines with more resources than you actually have with type 1 hypervisors. You may allocate 24GB of RAM to each of your eight virtual machines, for instance, if your server has 128GB of RAM.
The total amount of RAM is 192GB, but only 24GB of it will be used by the virtual machines on the real server. Even if they only consume the amount of RAM required for specific tasks, the VMs nevertheless recognize that they have 24GB available.
Drawbacks
- Insufficient functionality
Type 1 hypervisors are not very feature-rich and are rather straightforward. Basic functions like changing the date and time, IP address, password, etc. are included in the functionality.
- Difficult management
You need a management console installed on another machine in order to create virtual instances. You may control your virtual environment by connecting to the server’s hypervisor using the console.
- Price
The price of licenses for management consoles varies greatly depending on the functionalities you require.
Hypervisor Type 2
Hosted hypervisors are Type 2 hypervisors that operate inside the operating system of the physical host computer. Hosted hypervisors have one software layer between them and the hardware, in contrast to bare-metal hypervisors, which operate directly on the hardware. The hardware that houses the hypervisor:
- An actual device.
- A software program placed on the apparatus (Windows, Linux, macOS).
- A type 2 hypervisor program runs under that OS.
- Instances of a guest virtual machine.
What is a Hypervisor and Its Types? Usually, settings with a few servers will contain Type 2 hypervisors.
They are practical since they can be set up and managed without a management console on another system. The hypervisor-equipped server serves as the central processing unit, and virtual machines start up in typical OS windows.
Hosted hypervisors also operate as management consoles for virtual machines. With the help of the built-in functions, any task may be completed. Here is an illustration of a type 2 hypervisor interface from Oracle’s VirtualBox:
Benefits and Drawbacks of Type 2 Hypervisor
What is a Hypervisor and Its Types? The sections below summarize the main advantages and disadvantages.
Benefits
- Easy to manage
Your virtual environment can be created and maintained without the need to install additional software on a different computer. Install and use a type 2 hypervisor like any other OS program. You can import or export appliances, make snapshots or clones of your virtual computers, etc.
- Suited for testing
Type 2 hypervisors make it simple to test new applications and conduct research. It is possible to test how an application performs in various environments using numerous instances running under various operating systems on a single physical machine, or to build a specialized network environment. Only the availability of sufficient physical resources is required to maintain the host and virtual machines.
- Access to new tools for increasing productivity
The tools available on other operating systems can also be used by users of type 2 hypervisors in addition to their main OS. For instance, by setting up a Linux virtual computer, Windows users can access Linux programs.
Drawbacks
- A less flexible administration of resources
This sort of hypervisor makes resource allocation more challenging than type 1. Based on the specific VM’s present requirements, bare-metal hypervisors can dynamically allocate the resources that are currently available. Any resources that the user allows to a virtual machine are taken up by a type 2 hypervisor.
Even if a user just gives a virtual machine (VM) 8GB of RAM, that entire amount will be consumed. The user is left with 8GB of RAM to keep the actual computer operating if the host machine has 32GB of RAM and they build three VMs with 8GB each. The system would crash if a new VM with 8GB of RAM was created.
- The performance
The host OS puts more strain on the physical hardware, which could cause latency problems for the VMs.
- The security
On top of an operating system, type 2 hypervisors function. This aspect creates a potential risk because attackers might utilize possible OS flaws to access virtual computers.
Type 1 vs. Type 2 Hypervisor: Choosing the Right One
What is a Hypervisor and Its Types? Selecting the proper sort of hypervisor absolutely depends on your specific demands. The size of the virtual environment you wish to run should be your first consideration.
- You can select a type 2 hypervisor for private usage and smaller deployments. If money is not an issue, VMware will give you all the features you require. If not, Oracle VM VirtualBox is a hypervisor that will offer the majority of the necessary features.
- Type 1 hypervisors are the way to go for enterprise environments, but you must take numerous things into account before choosing one.
The cost of licensing is typically the most important factor in business. Since licensing may be per server, per CPU, or perhaps even per core, you should pay close attention. In the current market, Microsoft Hyper-V and VMware vSphere are in conflict. A few years ago, Hyper-V was lagging behind; today, it is a viable option, especially for bigger installations. KVM fits into this too.
Numerous manufacturers provide a variety of goods and levels of licensing to suit any enterprise. You might want to make a list of the requirements, including the number of virtual machines you require, the maximum resources per VM, the number of nodes in the cluster, the required functionalities, etc. then determine which of these items best suits your requirements.
Conclusion
What are a Hypervisor and what two different types of hypervisors (type 1 and type 2) have been covered in this article? Vendors of hypervisors offer bundles that include several products with various licensing arrangements. Before choosing a choice, you must conduct an in-depth study of your possibilities.
