Virtual Machines and Virtualization Technologies

This set of vocabulary flashcards covers the fundamental concepts, types, and management tools of virtual machines and containerization as presented in Chapter 14 of 'Operating Systems: Internals and Design Principles'.

Abstraction Layer

A software translation layer between software and physical hardware that manages computing resources by turning physical resources into logical or virtual resources.

Host

The underlying physical hardware system in a virtualization environment.

Virtual Machine Manager (VMM)

Also known as a hypervisor, this component creates and runs virtual machines by providing an interface that is identical to the host (except in paravirtualization).

Guest

A process, usually an operating system, provided with a virtual copy of the host.

Consolidation

The practice of sharing physical resources among multiple applications simultaneously to maximize efficiency.

Aggregating

The process of combining multiple physical resources into a single virtual resource.

Type 1 Hypervisor

A software layer loaded directly onto a physical server (bare metal) that directly controls physical resources and supports virtual machines as guests.

Type 2 Hypervisor

A software module that runs on top of a host operating system and relies on that OS to handle hardware interactions.

Live Migration

The process of moving a running virtual machine from one physical host to another with no interruption of user access.

Snapshot

A captured record of a virtual machine's state at a specific point in time, allowing it to be restored to 그 state later.

Paravirtualization

A software-assisted virtualization technique using specialized APIs and modified kernels to link virtual machines with the hypervisor for optimized performance.

AMD-V and Intel VT-x

Hardware-assisted virtualization extensions added to processors to enhance hypervisor performance.

Virtual Machine Extensions (VMX)

An extra instruction set offered by Intel processors to allow hypervisors to run more efficiently by performing operations directly on the processor.

Virtual Appliance

Standalone software packaged as a virtual machine image, consisting of a pre-configured set of applications and a guest OS.

Container Virtualization

An approach where software runs on top of a host OS kernel to provide isolated execution environments for applications while sharing a common kernel.

Kernel Control Groups (Cgroups)

A feature providing resource limiting, prioritization, accounting, and control (freezing/checkpointing) for groups of processes.

Microservices

Small deployable units that enable rapid updates and precise scalability by breaking down applications into manageable components.

Docker Image

Read-only templates used as the basis for instantiating Docker containers.

Docker Engine

The lightweight runtime package responsible for building and running Docker containers on a host system.

Docker Hub

A public repository and collaboration platform where users can store, share, and contribute custom Docker container images.

Memory Overcommit

A memory management strategy where the hypervisor allocates more virtual memory to guest VMs than is physically available on the host.

Ballooning

A memory management technique used by hypervisors to reclaim unused memory from guest operating systems.

Page Sharing

A memory management method where the hypervisor identifies identical memory pages across different VMs and stores only one physical copy to save RAM.