Week 10: Virtualization and Cloud Computing

Virtualization can make one physical computer look like several computers.

Cloud services can make infrastructure feel as if it disappeared completely.

It did not.

The hardware, storage, networking, operating systems, identities, and failure modes are still there. The boundary of responsibility moved.

A virtual machine still consumes real CPU time, real memory, real storage, and real network capacity. A container still depends on a host kernel and runtime. A VDI desktop still depends on the endpoint, network, identity service, broker, and virtualization infrastructure. A SaaS application still depends on identities, data, configuration, provider availability, and your organization's decisions.

The system question

Which layer owns the resource or decision that failed, and who is responsible for fixing it?

Virtualization adds layers:

physical hardware
      ↓
host / hypervisor / platform
      ↓
virtual resources
      ↓
guest or application environment
      ↓
user workload

Cloud adds an ownership question across those layers:

Which parts are mine to configure and repair, and which parts belong to the provider?

How the chapter moves

Lesson 1 explains why virtualization is useful for sandboxing, test and development, legacy support, cross-platform work, and application delivery without pretending virtual resources are free.

Lesson 2 compares Type 1 and Type 2 hypervisors, VDI, containers, virtual networking, storage, and security by their dependency chains.

Lesson 3 separates public, private, hybrid, and community cloud from IaaS, PaaS, and SaaS, then adds elasticity, availability, metering, multitenancy, and synchronization.

Lesson 4 turns those ideas into a bounded design problem where requirements choose the model, not the product name.

Lesson 5 troubleshoots resource exhaustion, virtual NICs, network modes, VDI, legacy isolation, snapshots, synchronization, and provider outages by responsibility boundary.

A technician who cannot identify the owner of the failed layer will troubleshoot the wrong system.