Virtualization and Cloud Computing

Week of 2026-11-03 · Download .docx

Objectives

Differentiate Type 1 and Type 2 hypervisors with examples
Compare IaaS, PaaS, and SaaS cloud service models
Explain the shared responsibility model and VM snapshots

Key terms

Type 1 hypervisor: Bare-metal hypervisor running directly on hardware without a host OS — ESXi, Hyper-V.
Type 2 hypervisor: Hosted hypervisor running on top of a host OS — VirtualBox, VMware Workstation.
VMware ESXi: Enterprise Type 1 bare-metal hypervisor by VMware/Broadcom.
VirtualBox: Free Type 2 hosted hypervisor by Oracle; runs on Windows, macOS, Linux.
VM snapshot: Captured state of a VM at a point in time; allows instant rollback.
Container: Lightweight isolated app environment sharing the host OS kernel; Docker, LXC.
IaaS: Infrastructure as a Service — provider gives VMs, storage, networking; customer manages OS up.
PaaS: Platform as a Service — provider manages OS and runtime; customer deploys applications.
SaaS: Software as a Service — provider manages everything; customer manages data only.
Shared responsibility: Security division: provider secures infrastructure; customer secures data and configurations.
Live migration: Moving a running VM between physical hosts with no downtime (VMware vMotion).
Microsoft 365: Example of SaaS — fully managed by Microsoft; users access via browser or client.

The concept

HYPERVISOR TYPES

A Type 1 (bare-metal) hypervisor installs directly on server hardware and controls all resources itself. Because there is no host OS layer consuming memory and CPU cycles, Type 1 hypervisors deliver better performance and stronger isolation for production use. Examples: VMware ESXi, Microsoft Hyper-V (in Server editions), and Proxmox.

A Type 2 (hosted) hypervisor runs as an application on top of an existing OS. The host OS must be running first; the hypervisor shares host resources and must contend with the host for CPU and memory. Examples: Oracle VirtualBox and VMware Workstation. Type 2 is ideal for development and learning environments on personal workstations.

CONTAINERS vs. VMs

Containers (Docker) share the host OS kernel and isolate processes using Linux namespaces and cgroups. This makes containers extremely lightweight — starting in milliseconds and using far less RAM than VMs. VMs each include a full OS kernel, making them heavier but more strongly isolated. VMs are appropriate when different OS versions are needed; containers excel for microservices.

CLOUD SERVICE MODELS

IaaS (Infrastructure as a Service) provides virtual hardware — VMs, storage, and networking — and the customer manages everything from the OS upward. PaaS adds the OS, runtime, and middleware, so developers only manage applications and data. SaaS is fully managed — the provider handles the entire stack and customers manage only their data and user access. Microsoft 365 (Teams, Outlook, Word) is SaaS.

SHARED RESPONSIBILITY

In the shared responsibility model, the cloud provider secures the physical hardware, data center, hypervisor, and network. The customer is responsible for identity management, access controls, data encryption, and application configuration. The exact split varies: IaaS customers have more responsibility than SaaS customers.

Worked examples

Example 1: An IT team plans to take a hypervisor server offline for hardware maintenance during business hours. Approach: Use live migration (vMotion on VMware) to move all running VMs to another host with zero downtime. Users will notice no interruption. After maintenance, migrate VMs back.

Example 2: A developer wants to test a new application on both Windows 10 and Ubuntu Linux without managing two physical machines. Solution: Install VirtualBox (Type 2 hypervisor) on their workstation. Create one VM for Windows 10 and one for Ubuntu. Take snapshots before major configuration changes for quick rollback.

Common mistakes

Confusing Type 1 (bare-metal, production) with Type 2 (hosted, desktop) — ESXi is Type 1, VirtualBox is Type 2.
Assuming a VM snapshot is a backup — snapshots live on the same datastore; they do not protect against hardware failure.
Confusing containers (share host kernel) with VMs (each have their own kernel).
Believing cloud providers handle all security — the shared responsibility model requires customers to secure data and access.
Thinking SaaS means on-premises software — SaaS is cloud-hosted and fully managed by the provider.

Self-check

Try each question before reading the answer. Answers at the bottom of this page.

1. A Type 1 hypervisor runs:

Directly on bare-metal hardware without a host OS
On top of a host OS
Inside a container
Only in public cloud

2. VirtualBox is an example of:

Type 2 (hosted) hypervisor
Type 1 (bare-metal) hypervisor
Container orchestrator
IaaS provider

3. IaaS provides:

VMs, storage, networking — customer manages OS and above
Fully managed application
Development platform
Physical hardware shipment

4. The shared responsibility model means:

Provider secures infrastructure; customer secures data and configurations
All security is the provider's responsibility
All security is the customer's responsibility
Always a 50/50 split

5. Microsoft 365 is an example of:

SaaS
IaaS
PaaS
Private cloud

Self-check answers

1. A — Type 1 is bare-metal — no host OS layer between the hypervisor and hardware.
2. A — VirtualBox is a Type 2 hosted hypervisor running as an application on a host OS.
3. A — IaaS provides virtualized infrastructure; customers manage OS, middleware, and applications.
4. A — Providers secure hardware and hypervisor; customers secure their data, identities, and configurations.
5. A — Microsoft 365 is SaaS — Microsoft manages the full stack; users manage only their data.

Canvas is the official record. This companion enhances the PGCC curriculum; it does not replace it. Last name and class year only. Students with a 504 plan or IEP: your accommodations apply.

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