What Is a Hypervisor and What Are Its Benefits? | Parallels Explains

In simple terms, a hypervisor is a software layer that creates and runs many isolated virtual machines (VMs) over single hardware. Before dwelling on the details of what a hypervisor is, it makes sense to understand the technology that is tied to it – virtualization.

Virtualization is essentially the creation of a virtual form of a resource (server, desktop, operating system, storage space, network, or files). The virtualization process partitions the underlying hardware so that each partition runs as a separate, isolated virtual machine. This is where the hypervisor steps into the equation.

A hypervisor can also be thought of as the operating system for virtualized systems. It is software that partitions, abstracts, and isolates OS and applications from the underlying computer hardware.

What are the Features of a Hypervisor?

There are various major features of hypervisors, including:

Partitioning

Hypervisors partition the underlying hardware. Partitioning is a method for efficiently using an abundance of hardware resources by enabling multiple independent software payloads to run concurrently on the same hardware.

Resource Distribution

Hypervisors manage independent virtual machines by distributing resources like memory, network bandwidth, etc. among them.

Virtual Machine Management

Upon the request of the user, hypervisors can start/stop the independent virtual machines.

Isolation

Hypervisors ensure that the virtual machines are isolated from each other. This helps ensure that a problem in one virtual machine does not affect the other.

Communication

The hypervisor also handles the communication amongst virtual machines over virtual networks, enabling VMs to connect with one other.

How Does a Hypervisor Work?

  1. Hypervisors operate on the server level and can be either physical or virtual, and hardware or software-defined
  2. Hypervisors load the client operating systems of the VMs
  3. The hypervisor distributes the computing resources such as CPU, memory, bandwidth, and disk storage for each of the VMs. It does this by creating pools of hardware resources, which it then allocates to VMs.
  4. VMs can create requests for the hypervisor through API calls.

What Types of Hypervisors Are There?

Type I / Bare-metal / Native Hypervisors

Type I hypervisors are also called bare-metal or native hypervisors. They run the host machine’s hardware directly, so the hypervisor software is the operating system. In simple terms, the hypervisor has direct hardware access, without any other software interfering.

Type I hypervisors are the best for enterprise computing and large-scale deployments. The advantages of Type I hypervisors are:

Scalability

The ability to directly assign resources makes Type I hypervisors scalable.

Optimization of physical resources

Type I hypervisors allow optimization of single server hardware, thus freeing up data costs and cutting down energy usage.

Better Resource Allocation

Type I hypervisors give administrators the ability to set resource allocation manually. Resource management is a dynamic and customized option in Type I hypervisors.

Examples: VMWare’s ESXi, Microsoft’s Hyper-V, VMware ESX/ESXi, KVM, Oracle VM Server, Citrix Hypervisor.

Type II / Embedded / Hosted Hypervisors

Type II hypervisors are also called embedded or hosted hypervisors.  These hypervisors are built on top of the operating system and rely on the host machine’s underlying operating system.

Also referred to as the hosted hypervisor, this hypervisor runs as an application within the operating system, which in turn runs directly on the host computer. Type II hypervisors also support multiple guest machines but are not allowed to directly access the host hardware and its resources. The pre-existing operating system manages the memory, network, and storage allocation, creating a certain amount of latency and restrictions. In addition, if the OS crashes, the hypervisor will also crash, and possible data loss might occur.

The advantages of Type II hypervisors are:

Easier setup

These hypervisors are easier to set up and manage as there is an underlying operating system to work with.

Easier management

Type II hypervisors do not require a dedicated administrator.

Compatibility

Type II hypervisors are compatible with a wider range of hardware, since they run on top of an OS, instead of specific hardware machines.

Examples: Oracle Solaris Zones, Oracle VM Server for x86, Oracle VM Virtual Box, VMWare Workstation, VMware Fusion and more.

KVM hypervisor

KVM (Kernel-based Virtual Machine) is the mix of Type I and Type II hypervisor. It is built into Linux, and it turns Linux into a Type I hypervisor. This type of hypervisor:

Differences between a Hypervisor and a Container

At higher levels, a hypervisor and a container provide similar functionalities. They both provide an isolated and packaged environment containing various IT components. However, each is different in how it handles scalability and portability. A hypervisor abstracts the underlying hardware from the host’s operating system and apps and is the core technology behind virtualization.

A hypervisor allows a physical server to operate multiple VMs as guests running alongside each other.  Each VM can run a different OS. A hypervisor allocates each VM resources such as CPU, memory, storage and network to run the guest OS and applications. Since each VM contains the virtualized hardware, guest OS, and installed applications, a hypervisor consumes more computing resources.

In contrast, a container through a containerization engine packages an application together with its binaries and other dependencies into a single unit. Once packaged, you can run containers on any platform provided you’ve installed a corresponding container engine. This way, a container engine performs the same function that a hypervisor does for VMs.

While a hypervisor abstracts the hardware resources for multiple VMs to run their own OSs, a container engine abstracts the OS to allow containers to run multiple applications. Since containers share the same OS kernel, containers are lightweight, boot quickly, and maximize the server resources utilization.

Benefits of Using Hypervisors

Data Replication

Cloning and replicating virtual machines is difficult. Storage-based replication methods require replicating the entire volume of all the virtual machines in your server. If there are a lot of virtual machines in your server then replicating the entire volume requires massive amounts of storage space.

Hypervisors can be used for easy cloning and replication. Hypervisor-based replication is easier and more cost-effective than any other replication method of virtual machines.

With hypervisor-based replication you can simply choose the VMs and the parts that are to be replicated, saving up on storage space. Hypervisor-based replication is also hardware neutral, meaning that you can store any data duplicates to any storage device with ease.

Consolidating Servers

Hypervisors also offer inbuilt graphical dashboards. You can also download additional enhancements to the inbuilt dashboards for better visibility. This ability lets you consolidate and manage your servers centrally even when they are running different operating systems.

Desktop Virtualization

Hypervisors can also be efficiently used for desktop virtualization. You can easily host a virtual desktop on a server, and the desktop replicates the user’s physical desktop. This lets employees access their workstations over the Internet through client devices, allowing them to work remotely.

Which Type of Hypervisor is Best for You?

The hypervisor you choose depends greatly on your needs as an organization, the cost that your organization is ready to bear, and the expertise that you have inside your organization to manage virtual machines.

Small Businesses

On a general basis, it makes sense for small businesses to adopt Type II hypervisors.

Type II hypervisors have lower costs, are easier to set up, and do not require a dedicated administrator to manage them. They work well for small organizations where latency is not an issue, and when the number of virtual machines required is comparatively low.

Large Corporations

Large corporations and businesses require many virtual machines for their deployments. In such a case the Type I hypervisor is more suitable.

Type I hypervisors have low latency times, as they can access the hardware directly. They are widely acknowledged as the best performing and most efficient hypervisors that require an administrator to manually set resource allocation based on the application’s priority. They might go higher in terms of costs because of the need to deploy on bare metal. However, they win in terms of security as they isolate virtual machines from each other.

Parallels RAS: A Cost-Effective Virtualization Solution

Parallels® Remote Application Server (RAS) is a virtualization solution that enables businesses to publish both applications and desktops to any device using a single license. It is complete, easy to deploy, and cost-effective. One of the key features of Parallels RAS infrastructure is the ability to publish VDI desktops. These VDI desktops are, in turn, hosted in hypervisors.

The best feature provided by Parallels RAS when it comes to virtualization is the support for all the major hypervisors  (Microsoft Hyper-V, VMware ESXi, Scale Computing HC3 and Nutanix Acropolis). This flexibility allows businesses to adopt virtualization without having to worry about vendors.

Additionally, Parallels RAS also supports multiple hypervisors under the same infrastructure, allowing existing infrastructures to be managed from the Parallels RAS Console with ease.

The Parallels RAS Console enables administrators to both configure and administer different hypervisors from a central location. Parallels RAS also supports multiple OSs under the same pool of resources, even from different hypervisors. Additionally, it allows IT administrators to:

Download the 30-day trial to reap the benefits of virtualization with Parallels RAS!


References:

networkworld.com

redhat.com

techtarget.com

pluralsight.com

blog.resellerclub.com

parallels.com