Virtualization & Cloud
See how virtual machines use real hardware resources, then separate cloud deployment models from cloud service models.
Mission goal
Explain how virtualization separates logical computers from physical hardware, identify Type 1 and Type 2 hypervisors, connect virtual machines to CPU/memory/storage/network resources, and compare cloud characteristics, deployment models, and service models.
8.1 • Hypervisors: where does the virtualization layer live?
Type 1
Installed directly on the hardware. The module gives Hyper-V and VMware ESXi as examples.
Picture it: Hardware → Hypervisor → Virtual Machines.
Type 2
Installed as an application on top of a host operating system. The module gives Oracle VirtualBox and Parallels Workstation as examples.
Picture it: Hardware → Host OS → Hypervisor application → Virtual Machines.
A virtualization product runs as an app inside the user’s existing OS. Type 1 or Type 2?
Type 2.
A hypervisor is installed directly on server hardware. Type 1 or Type 2?
Type 1.
Why virtualize?
| Use | What it means in the module |
|---|---|
| Sandboxing | Use an isolated virtual environment for work that should not directly affect the normal host environment. |
| Legacy OS hosting | Run an older operating system inside a VM when needed. |
| Cross-platform | Use virtualization to run a different OS/platform from the host. |
| Training / labs | Create repeatable practice systems without requiring a separate physical computer for every environment. |
| Server virtualization | Host additional network nodes as virtual systems. |
| Virtual desktop | Provide employees a VM desktop rather than a traditional local desktop system. |
| Application / container | The module identifies application virtualization and containers as additional virtualization approaches. |
A VM still needs real resources
CPU
The processor must support the required virtualization technology, and virtualization extensions may need to be enabled in BIOS or UEFI firmware.
Memory
Allocated memory must be sufficient for the guest operating system and its applications.
Mass storage
VMs can share physical storage while using separate logical storage such as virtual disks.
Networking
Networking may be needed VM-to-VM, VM-to-host, and VM-to-the-host-network.
A VM will not start because hardware virtualization support is disabled. Where does the module tell you to look?
Firmware settings such as BIOS or UEFI, assuming the CPU supports virtualization technology.
Virtualization security: three layers to think about
| Layer | Risk / responsibility |
|---|---|
| Guest OS | The guest operating system still requires security; being virtual does not remove OS security needs. |
| Host | The host can become a single point of failure: if it goes offline, the virtualized nodes on it can also go down. |
| Hypervisor | The virtualization platform itself must be monitored for vulnerabilities. |
One physical host runs six VMs and the host fails. Why is the impact larger than one normal PC failing?
The host is a single point of failure for all virtualized nodes running on it.
8.2 • Cloud characteristics
High availability
Designed for minimal downtime.
Shared resources
Cloud environments can pool resources for use by multiple workloads or customers.
Scalability
Expand or contract the virtual environment based on demand.
Elasticity
Expand or contract without affecting service or performance.
Cloud deployment models: who uses the environment?
| Model | Core idea |
|---|---|
| Public | Provider cloud using multitenancy. |
| Private | Dedicated to a single customer; the module notes hosted private-cloud services can exist within a public provider while remaining dedicated. |
| Community | A deployment model shared around a community of users/organizations. |
| Hybrid | Combines deployment approaches. |
Cloud service models: what layer are you receiving?
| Model | Module description | Think |
|---|---|---|
| IaaS | Servers, storage, networking, load balancers. | Infrastructure building blocks |
| PaaS | Servers/storage plus tools for application development/deployment such as databases. | Development platform |
| SaaS | Application fully run in the cloud environment. | Use the application |
| DaaS | Desktop as a Service. | Receive a cloud-hosted desktop |
You need cloud servers, storage, and networking to build your own environment. Which model?
Infrastructure as a Service (IaaS).
You mainly need the finished cloud application rather than managing the infrastructure. Which model?
Software as a Service (SaaS).
Cloud file storage
The module highlights file synchronization for tracking changes across multiple platforms, possible commenting features, and Content Delivery Networks (CDNs) that replicate content across multiple datacenters.
Interactive model check
Scenario: “A developer needs servers, storage, and development/deployment tools such as databases.”
Self-check
- Draw the Type 1 and Type 2 stacks from memory.
- Explain why a host can be a single point of failure.
- Explain deployment model vs. service model.
- Give one module use for virtualization.
Virtualization & Cloud Decision Lab
Use the requirement in each scenario to identify the virtualization or cloud concept that best fits Module 8.
Challenge 1
A hypervisor runs directly on the physical hardware rather than inside a desktop operating system. Which type?
Challenge 2
A learner installs virtualization software inside an existing desktop operating system for a lab. Which type?
Challenge 3
A virtual machine is slow because the host has too little memory for all running guests. Which resource is the immediate clue?
Challenge 4
A customer wants to use a finished cloud application without managing the operating system or application platform. Which model?
Challenge 5
A developer wants a managed application platform rather than managing the underlying infrastructure. Which model?
Challenge 6
A customer needs cloud-hosted compute/infrastructure resources and expects more responsibility for what runs on them. Which model?
Challenge 7
Demand rises quickly and resources need to grow and shrink with that demand. Which cloud characteristic is the strongest clue?
Challenge 8
An organization combines private resources with public cloud resources. Which deployment model?
Rapid retrieval checks
Say your answer first, then open the explanation.
What is a host?
The physical system and environment providing resources for virtualization.
What is a guest?
A virtual machine/operating system running on the virtualized host.
Why can too many VMs cause problems?
VMs still consume physical CPU, RAM, storage, and networking resources from the host.
Type 1 vs. Type 2 in one sentence?
Type 1 runs on hardware; Type 2 runs inside a host operating system.
Scalability vs. elasticity?
Scalability is the ability to increase capacity; elasticity emphasizes adjusting resources with changing demand.
Why does virtualization not remove security responsibilities?
Hosts, guests, hypervisors, accounts, networks, and stored data still need appropriate protection.