A virtual machine (VM) is a complete emulation of a physical computer system. It operates on a hypervisor, which abstracts the physical hardware of the host machine. Each VM encapsulates its own full guest operating system (OS), kernel, applications, binaries, and libraries. This self-contained nature ensures strong isolation from the host OS and any other VMs running on the same physical hardware. This isolation is a core principle of Type-1 and Type-2 hypervisors, preventing processes or failures within one VM from impacting the host or other guest environments.

A. This describes containers. Containers share the host OS kernel and often its binaries and libraries, which is why they are more lightweight than VMs.

B. VMs are less resource-efficient than containers because each VM requires a full guest OS, consuming significant CPU, memory, and storage overhead.

D. VMs are considered heavyweight due to the inclusion of a complete guest OS, making them significantly less lightweight than containers.

1. Official Vendor Documentation (VMware): VMware

Inc. "What is a Virtual Machine?" VMware Glossary. "Virtual machines are isolated from one another and use their own guest OS

which means that if one crashes

it won’t affect the others. This isolation also boosts security

as malware in one VM won’t spread to the others." Retrieved from the official VMware website.

2. Official Vendor Documentation (Red Hat): Red Hat

Inc. "What is virtualization?" Red Hat Customer Portal. "A virtual machine is a software-based computer that runs on a physical computer... Each VM has its own operating system (OS) and functions separately from the other VMs

even when they are all running on the same host." This document explicitly confirms the isolated OS characteristic.

3. Official Vendor Documentation (Cisco): Wallace

K.

et al. (2020). CCNP and CCIE Enterprise Core ENCOR 350-401 Official Cert Guide. Cisco Press. Chapter 2

"Virtualization Fundamentals

" section "Virtual Machines

" explains that a hypervisor creates VMs

each with its own OS

applications

and virtual hardware

providing isolation from the host.