Virtual machine: Difference between revisions

Latest revision as of 02:57, 11 December 2024

Virtual Machine

A screenshot of VirtualBox, a popular virtual machine software.

Diagram illustrating hardware virtualization.

A virtual machine (VM) is a software emulation of a physical computer that runs an operating system and applications just like a physical computer. Virtual machines are created and managed by a hypervisor, which is a layer of software that allows multiple VMs to run on a single physical machine, sharing its resources.

Overview[edit]

Virtual machines are a key component of virtualization, a technology that allows for the abstraction of computer resources. By using virtualization, multiple operating systems can run on a single physical machine, each in its own isolated environment. This is particularly useful for server consolidation, testing and development, and running applications that require different operating systems.

Types of Virtual Machines[edit]

There are two main types of virtual machines:

System Virtual Machines: These provide a complete system platform that supports the execution of a complete operating system. Examples include VMware Workstation, VirtualBox, and Microsoft Hyper-V.

Process Virtual Machines: These are designed to run a single program or process. An example is the Java Virtual Machine (JVM), which allows Java applications to run on any device that has the JVM installed.

How Virtual Machines Work[edit]

Virtual machines operate by using a hypervisor, which can be either a Type 1 (bare-metal) or Type 2 (hosted) hypervisor.

Type 1 Hypervisors: These run directly on the physical hardware and manage the virtual machines. Examples include VMware ESXi and Microsoft Hyper-V.

Type 2 Hypervisors: These run on top of an existing operating system. Examples include Oracle VirtualBox and VMware Workstation.

The hypervisor allocates resources such as CPU, memory, and storage to each virtual machine, ensuring that they operate independently of each other.

Benefits of Virtual Machines[edit]

Virtual machines offer several advantages:

Isolation: Each VM is isolated from others, providing security and stability.
Resource Efficiency: Multiple VMs can share the same physical resources, reducing hardware costs.
Flexibility: VMs can be easily created, modified, and deleted, making them ideal for testing and development.
Portability: VMs can be moved between different physical machines, providing flexibility in deployment.

Challenges of Virtual Machines[edit]

Despite their benefits, virtual machines also present some challenges:

Performance Overhead: VMs may have a performance overhead compared to running directly on physical hardware.
Complexity: Managing multiple VMs and hypervisors can be complex.
Security: While VMs are isolated, vulnerabilities in the hypervisor can potentially affect all VMs.

Also see[edit]

@@ Line 1: / Line 1: @@
-== Virtual Machine ==
+Virtual Machine
-A virtual machine (VM) is a software emulation of a physical computer system. It allows users to run multiple operating systems and applications on a single physical machine, providing a cost-effective and efficient way to utilize computing resources. In this article, we will explore the concept of virtual machines, their benefits, and their various applications.
+[[File:VirtualBox2.png|thumb|A screenshot of VirtualBox, a popular virtual machine software.]]
+[[File:Hardware Virtualization (copy).svg|thumb|Diagram illustrating hardware virtualization.]]
-=== Overview ===
+A '''virtual machine''' (VM) is a software emulation of a physical computer that runs an operating system and applications just like a physical computer. Virtual machines are created and managed by a hypervisor, which is a layer of software that allows multiple VMs to run on a single physical machine, sharing its resources.
-A virtual machine is created by using virtualization software, which enables the creation and management of multiple virtual environments on a single physical machine. Each virtual machine operates independently, with its own operating system and applications, as if it were a separate physical computer.
+== Overview ==
+Virtual machines are a key component of [[virtualization]], a technology that allows for the abstraction of computer resources. By using virtualization, multiple operating systems can run on a single physical machine, each in its own isolated environment. This is particularly useful for [[server consolidation]], testing and development, and running applications that require different operating systems.
-Virtual machines are commonly used in server environments, where they allow for the consolidation of multiple servers onto a single physical machine. This helps to reduce hardware costs, simplify management, and improve resource utilization. Additionally, virtual machines provide a level of isolation between different applications and operating systems, enhancing security and stability.
+== Types of Virtual Machines ==
+There are two main types of virtual machines:
-=== Benefits ===
+* '''System Virtual Machines''': These provide a complete system platform that supports the execution of a complete operating system. Examples include [[VMware Workstation]], [[VirtualBox]], and [[Microsoft Hyper-V]].
-There are several key benefits to using virtual machines:
+* '''Process Virtual Machines''': These are designed to run a single program or process. An example is the [[Java Virtual Machine]] (JVM), which allows Java applications to run on any device that has the JVM installed.
-. **Hardware Consolidation**: Virtual machines enable the consolidation of multiple servers onto a single physical machine, reducing hardware costs and energy consumption.
+== How Virtual Machines Work ==
+Virtual machines operate by using a hypervisor, which can be either a Type 1 (bare-metal) or Type 2 (hosted) hypervisor.
-. **Resource Utilization**: By running multiple virtual machines on a single physical machine, computing resources can be efficiently utilized, maximizing the overall performance of the system.
+* '''Type 1 Hypervisors''': These run directly on the physical hardware and manage the virtual machines. Examples include [[VMware ESXi]] and [[Microsoft Hyper-V]].
-. **Isolation**: Each virtual machine operates independently, providing a level of isolation between different applications and operating systems. This helps to enhance security and stability, as issues in one virtual machine do not affect others.
+* '''Type 2 Hypervisors''': These run on top of an existing operating system. Examples include [[Oracle VirtualBox]] and [[VMware Workstation]].
-. **Flexibility**: Virtual machines can be easily created, cloned, and migrated between physical machines, providing flexibility in managing and scaling computing resources.
+The hypervisor allocates resources such as CPU, memory, and storage to each virtual machine, ensuring that they operate independently of each other.
-=== Applications ===
+== Benefits of Virtual Machines ==
+Virtual machines offer several advantages:
-Virtual machines have a wide range of applications in various industries and environments. Some common use cases include:
+* '''Isolation''': Each VM is isolated from others, providing security and stability.
+* '''Resource Efficiency''': Multiple VMs can share the same physical resources, reducing hardware costs.
+* '''Flexibility''': VMs can be easily created, modified, and deleted, making them ideal for testing and development.
+* '''Portability''': VMs can be moved between different physical machines, providing flexibility in deployment.
-. **Server Virtualization**: Virtual machines are extensively used in server environments to consolidate multiple servers onto a single physical machine. This helps to reduce hardware costs, simplify management, and improve resource utilization.
+== Challenges of Virtual Machines ==
+Despite their benefits, virtual machines also present some challenges:
-. **Software Development and Testing**: Virtual machines provide developers with a sandboxed environment to develop and test software applications. They can easily create multiple virtual machines with different operating systems and configurations to test compatibility and performance.
+* '''Performance Overhead''': VMs may have a performance overhead compared to running directly on physical hardware.
+* '''Complexity''': Managing multiple VMs and hypervisors can be complex.
+* '''Security''': While VMs are isolated, vulnerabilities in the hypervisor can potentially affect all VMs.
-. **Legacy Application Support**: Virtual machines can be used to run legacy applications that are not compatible with modern operating systems. By running the legacy application in a virtual machine, organizations can continue to use the application without the need for dedicated hardware.
+== Also see ==
+* [[Virtualization]]
+* [[Hypervisor]]
+* [[Cloud computing]]
+* [[Containerization]]
+* [[Java Virtual Machine]]
-. **Desktop Virtualization**: Virtual machines can be used to provide virtual desktop infrastructure (VDI), allowing users to access their desktop environment from any device. This enables remote work, improves security, and simplifies desktop management.
+{{Virtualization}}
-=== Conclusion ===
-Virtual machines have revolutionized the way computing resources are utilized and managed. They provide a cost-effective and efficient solution for running multiple operating systems and applications on a single physical machine. With their benefits of hardware consolidation, resource utilization, isolation, and flexibility, virtual machines have become an integral part of modern computing environments.
-[[Category:Computing]]
 [[Category:Virtualization]]
-[[Category:Software]]
+[[Category:Computer architecture]]
-[[Category:Operating Systems]]
-[[Category:Computer Science]]
-{{stub}}