Virtualization is a technology that enables the creation and operation of multiple virtual environments or virtual machines (VMs) on a single physical computer or server. It allows you to abstract the hardware resources of a computer, such as the CPU, memory, storage, and network, and allocate them to multiple VMs, each running its own operating system (OS) and applications. This concept of running multiple VMs on a single physical machine provides various benefits, including improved resource utilization, flexibility, scalability, and cost savings.
Virtualization works by introducing a software layer called a hypervisor or virtual machine monitor (VMM) between the physical hardware and the operating systems running on the VMs. The hypervisor acts as a mediator, managing and controlling the hardware resources and providing a virtualized environment for each VM.
Types of Hypervisor
There are two types of hypervisor .These are Bare-Metal Hypervisors and Hosted Hypervisors.
- Bare-Metal Hypervisors :- Bare-Metal Hypervisors hypervisors run directly on the physical hardware without the need for a host operating system. They have direct access to the hardware resources and provide better performance and efficiency. Examples of type 1 hypervisors include VMware ESXi, Microsoft Hyper-V, and Xen.
- Hosted Hypervisors :- These hypervisors run on top of a host operating system, which then runs on the physical hardware. They rely on the host OS to manage hardware access. Type 2 hypervisors are typically used for desktop virtualization scenarios. Examples of type 2 hypervisors include VMware Workstation, Oracle VirtualBox, and Microsoft Virtual PC.
Once the hypervisor is installed, it creates and manages virtual machines. Each VM emulates a complete computer system, including virtualized hardware components such as virtual CPUs, virtual memory, virtual disks, and virtual network interfaces. The hypervisor allocates and shares the physical hardware resources among the VMs, ensuring that each VM gets its fair share of resources while isolating them from one another.
When a VM is powered on, the hypervisor intercepts the hardware requests made by the VM and translates them into instructions that can be executed on the physical hardware. For example, when a VM running on a hypervisor requests CPU time, the hypervisor schedules and shares the available CPU cycles among the running VMs. Similarly, the hypervisor manages the memory allocation, disk storage, and network connectivity for each VM.
Virtualization also provides features such as snapshotting and cloning, which allow you to capture the state of a VM at a particular moment and create exact copies of VMs, respectively. This can be useful for backup and disaster recovery purposes or for quickly provisioning new VMs from existing templates.
Moreover, virtualization enables the migration of VMs between physical hosts without disrupting their operations. This process is known as live migration or vMotion. Live migration allows you to move VMs from one server to another, even across different physical machines or data centers, while keeping the VMs running continuously. This feature is beneficial for load balancing, hardware maintenance, and maximizing resource utilization.
Another key aspect of virtualization is the ability to run multiple operating systems simultaneously on a single physical machine. This allows you to consolidate multiple servers or workstations into a smaller number of physical machines, reducing hardware costs, power consumption, and data center space requirements.
Virtualization also plays a crucial role in cloud computing. Cloud service providers leverage virtualization technologies to offer Infrastructure as a Service (IaaS) solutions, where customers can provision and manage VMs in the cloud, and Platform as a Service (PaaS) solutions, which provide higher-level abstractions such as application runtimes or databases.
In summary, virtualization is the process of creating virtual machines that run on a single physical computer, abstracting and sharing its hardware resources among the VMs. The hypervisor acts