A virtual machine (VM) is a software-based emulation of a physical computer that runs an operating system (OS) and applications just like a physical machine. VMs are created and managed by a hypervisor, a layer of software that enables multiple VMs to share the physical resources of a single host machine.
This technology allows for the efficient use of hardware resources and provides numerous advantages in various computing environments.
What is a virtual machine?
Hypervisor
The hypervisor, also known as a virtual machine monitor (VMM), is responsible for creating, running, and managing VMs. There are two types of hypervisors:
Type 1 (Bare-metal)
Runs directly on the physical hardware (e.g., VMware ESXi, Microsoft Hyper-V).
Type 2 (Hosted)
Runs on top of an existing operating system (e.g., Oracle VirtualBox, VMware Workstation).
Hypervisor
Virtualization
Virtualization is the underlying technology that enables the creation of VMs. It abstracts the hardware resources of a physical machine, allowing multiple VMs to run concurrently on a single physical server.
Each VM operates independently, with its own OS and applications.
Virtualization allows for the creation of a environment that emulates physical hardware.
Guest OS
The operating system that runs within a virtual machine is referred to as the guest OS. It can be different from the host OS (the OS running on the physical hardware), enabling users to run multiple operating systems on the same hardware.
Each virtual machine has its own , which can be different from the host system.
Virtual Hardware
Each VM is allocated virtual hardware components (CPU, memory, disk space, and network interfaces) that simulate physical hardware. This allows the guest OS and applications to interact with the virtualized resources as if they were running on a physical machine.
Benefits of Virtual Machines
Resource Efficiency
VMs allow multiple operating systems and applications to run on a single physical server, optimizing hardware utilization and reducing costs.
Isolation
Each VM operates in its own isolated environment, which enhances security and stability. If one VM crashes or is compromised, it does not affect the other VMs running on the same host.
Scalability
Virtual machines can be easily created, cloned, and migrated across physical servers, enabling organizations to scale their infrastructure quickly in response to changing demands.
Testing and Development
Developers can use VMs to create isolated environments for testing applications without affecting the host system. This is particularly useful for software development and quality assurance.
Legacy Software Support
Virtual machines can run older operating systems, allowing organizations to maintain compatibility with legacy applications that may not run on newer hardware or operating systems.
Virtual machines can help in of applications for security purposes.
How does virtualization save energy?
Use Cases
Server Consolidation
Organizations can consolidate multiple physical servers into fewer VMs on a single host, reducing hardware costs and improving resource utilization.
Development and Testing
VMs provide a flexible environment for developers to test applications across different operating systems and configurations.
Cloud Computing
Cloud service providers utilize virtualization to deliver scalable and flexible computing resources to users.
Disaster Recovery and Backup
VMs facilitate easy backup and recovery processes, ensuring business continuity in case of hardware failures.
Virtual machines are commonly used for new software in a safe environment.
