What is a hypervisor?
A hypervisor is a software that you can use to run multiple virtual machines on a single physical machine. Every virtual machine has its own operating system and applications. The hypervisor allocates the underlying physical computing resources such as CPU and memory to individual virtual machines as required. Thus, it supports the optimal use of physical IT infrastructure.
Why is a hypervisor important?
Hypervisors are the underlying technology behind virtualization or the decoupling of hardware from software. IT administrators can create multiple virtual machines on a single host machine. Each virtual machine has its own operating system and hardware resources such as a CPU, a graphics accelerator, and storage. You can install software applications on a virtual machine, just like you do on a physical computer.
The fundamentals of virtual machines and other virtualization technologies have enabled cloud computing services in enterprise applications. They allow you to scale computing services efficiently on limited hardware infrastructure. For example, different business departments can run different workloads separately by using multiple virtual machines on a single server.
What are the benefits of a hypervisor?
Organizations use virtualization software like hypervisors because the software helps them to use resources efficiently and reduce hardware investment. Virtualization brings several other benefits such as those given below.
A hypervisor abstracts the host's hardware from the operating software environment. IT administrators can configure, deploy, and manage software applications without being constrained to a specific hardware setup. For example, you can run macOS on a virtual machine instead of iMac computers.
Hypervisors make setting up a server operating system more efficient. Manually installing the operating system and related software components is a time-consuming process. Instead, you can configure the hypervisor to immediately create your virtual environment.
Organizations use hypervisors to maximize resource usage on physical computers. Instead of using separate machines for different workloads, hypervisors create multiple virtual computers to run several workloads on a single machine. This translates to faster scalability and reduced hardware expenditure for organizations.
IT teams can allocate memory, networking, processing, and storage resources across multiple servers as needed. They have the ability to shift workloads between machines or platforms easily. When an application requires more processing power, the hypervisor provides seamless access to additional physical resources.
What are the use cases for hypervisors?
Virtualization software that are powered by hypervisors have several use cases. We give some examples below.
Employees use desktop virtualization software to emulate a version of their workstation computing environment on the server. This allows them to access their work applications and files remotely.
Companies use hypervisors to consolidate multiple computers that perform different functions into a single server. For example, if production, marketing, and customer support teams run their workloads on individual physical servers, it can result in idle resources. With a hypervisor, you can host the virtual machines for the respective business units on a single server, even if they require different operating systems and software components.
The hypervisor captures snapshots of the virtual machine’s previous state in a virtual machine image—a file that contains the installation instructions, configurations, and other details of the virtual machine. System administrators can use the image file to restore the virtual machine in case of failure. There is also capability to create backup copies or move the virtual machine to a different host.
Legacy system continuity
Some organizations have invested significantly in software that has outlasted the underlying server. Hypervisors provide an option to continue running the software by virtualizing the hardware environment required. This allows organizations to support their cloud transformation efforts with minimum disruption to existing business workflows.
How does a hypervisor work?
System administrators install the hypervisor software on physical servers. The hypervisor loads the virtual machine images to create multiple virtual operating systems. The physical machine is known as a host, and the virtual operating systems are guests.
The hypervisor ensures that each virtual machine receives the allocated resources as configured. It does so by acting as an intermediary between guest machines and the underlying physical hardware. The hypervisor relays requests for processing power, memory, storage, and other resources to the host machine in several ways, including API calls. An API is a software communication method that allows different applications to exchange data.
What are the types of hypervisors?
There are two types of hypervisors, each differing in architecture and performance.
Type 1 hypervisor
The type 1 hypervisor sits on top of the metal server and has direct access to the hardware resources. Because of this, the type 1 hypervisor is also known as a bare-metal hypervisor. The host machine does not have an operating system installed in a bare-metal hypervisor setup. Instead, the hypervisor software acts as a lightweight operating system.
Pros and cons
Due to its architecture, the type 1 hypervisor is very efficient. It can directly manage and allocate resources for multiple virtual machines without going through the host operating system. These types of hypervisors are also more secure, as the absence of a host operating system reduces the risks of instability.
Type 2 hypervisor
The type 2 hypervisor is a hypervisor program installed on a host operating system. It is also known as a hosted or embedded hypervisor. Like other software applications, hosted hypervisors do not have complete control of the computer resources. Instead, the system administrator allocates the resources for the hosted hypervisor, which it distributes to the virtual machines.
Pros and cons
The presence of the host operating system introduces latency to the virtualized environment. When the virtual machine requests computing resources, the hypervisor cannot directly access the underlying hardware but relays the request to the host operating system. Also, the hypervisor and its hosted virtual machines are dependent on the stability of the host operating system.
Type 1 hypervisors compared to type 2 hypervisors
Despite their differences, both types of hypervisors are helpful in different applications. For example, enterprise cloud data centers use type 1 or bare-metal hypervisors because of their efficiency, scalability, and flexibility when allocating resources to virtual machines. Also, a type 1 hypervisor is generally more secure and stable because it does not run on top of another operating system.
Conversely, administrators use type 2 hypervisors because they are more user-friendly. Type 2 hypervisors are easier to install, configure, and use than bare-metal hypervisors. It is similar to installing and using other desktop applications.
What is a cloud hypervisor?
A cloud hypervisor consists of virtualization technologies that abstract the physical hardware resources of a cloud provider’s data center. They allow organizations to run distributed workloads on the cloud architecture. It allows multi-tenant cloud environments, where individual users or businesses can run workloads or store data in a logically independent compartment.
Cloud providers usually use bare-metal hypervisors to allocate virtualized hardware resources to users. For example, Amazon Elastic Compute Cloud (Amazon EC2) allows organizations to scale their cloud computing capacities with Xen-based hypervisors. It provides a cost-effective cloud solution where businesses only pay for the compute resources needed to run their AWS workload.
What is the difference between hypervisors and containers?
A container is a software package that stores all the necessary files and configurations to run an application on any operating system. Developers use containers to reduce software development complexities and improve efficiency when deploying the applications. A containerized application can run on a public, hybrid, or on-premises cloud with consistent performance because it is independent of the underlying operating system.
Both hypervisors and containers provide virtualization but at a different software layer. A hypervisor abstracts the hardware from the software environment. In contrast, a container runs in an environment where a container engine abstracts the operating system.
What are the security considerations for hypervisors?
Software programs on a virtual machine do not interfere with applications on other guest operating systems, which provides a degree of security. However, the virtualized environment relies on the hypervisor for a robust security posture. Any issues affecting the hypervisor will impact all virtual machines running on top of it. So, it’s essential to use a hypervisor with built-in safeguard measures to secure the workload’s integrity.
How does AWS help with hypervisors?
AWS Nitro System is a lightweight hypervisor that allows organizations to innovate faster in a secure cloud environment. It is a next-generation virtualization technology that delegates hypervisor management tasks to specific hardware and software. This enables AWS Nitro System to dedicate all of the compute resources to your AWS workload.
Here are some benefits of AWS Nitro System:
- AWS Nitro System continuously monitors the virtualized resources and prevents inadvertent access,
- Organizations achieve enhanced performance with dedicated Nitro Cards, including high-speed networking, high-speed Amazon Elastic Block Store (Amazon EBS), and I/O acceleration.
- AWS Nitro Enclaves allows organizations to create isolated compute environments to protect personally identifiable information (PII), financial data, and other sensitive information.
- AWS Nitro System is compatible with previous versions of EC2 instances. This allows organizations to run existing workloads on modern hardware and software components.
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