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EN_Virtualization

somaz edited this page Mar 30, 2026 · 9 revisions

Virtualization & Container Technology

A summary of virtualization concepts for DevOps engineers. Click each link for full details.


Glossary

Virtualization Concepts

  • Virtualization: Technology that creates virtual versions of physical devices or resources in software
  • Type 1 Hypervisor: Runs directly on bare-metal hardware (VMware ESXi, Microsoft Hyper-V)
  • Type 2 Hypervisor: Runs on top of a host OS — used for dev/test (VirtualBox, VMware Workstation)
  • Full Virtualization: Complete hardware emulation — guest OS requires no modification
  • Para-Virtualization: Guest OS is aware of the hypervisor and communicates directly — better I/O performance
  • Container Virtualization: Shares host OS kernel, isolates only the app and its dependencies — lighter than VMs (Docker, Kubernetes)

Storage Virtualization

  • RAID: Combines multiple physical disks into one logical unit — improves redundancy and performance
  • LVM (Logical Volume Manager): Abstraction layer over physical storage — flexible resizing without physical constraints

Docker Core Concepts

  • Docker: Container platform leveraging Linux cgroups, namespaces, and OverlayFS
  • Dockerfile: Text file defining image build instructions (FROM, RUN, COPY, CMD, EXPOSE, ENV)
  • Docker Compose: Tool to define and run multi-container apps using docker-compose.yml
  • Docker Hub: Public registry for Docker images
  • cgroups: Limits CPU, memory, and I/O resources per process group
  • Namespaces: Isolates PID, network, mount, and other resources per container

Q&A List

Q1: What is Virtualization?

Covers the concept of abstracting physical resources, comparison with RAID and LVM, full vs para-virtualization, and the differences between host, container, and hypervisor virtualization with their use cases.

Details


Q2: Docker & Dockerfile & Docker Compose

Covers how Docker works (cgroups, namespaces, OverlayFS), Dockerfile syntax and the image build process, and how to define multi-container services with Docker Compose.

Details


Reference

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