📘 07-03: Virtualization¶
❓ What Is Virtualization?¶
Virtualization abstracts physical hardware so multiple isolated systems run on one physical machine. It's the foundation of cloud computing.
📌 Hypervisors¶
A hypervisor (VMM) creates and runs virtual machines, allocating CPU/RAM/I/O and keeping VMs isolated.
| Type | Runs on | Examples | Use |
|---|---|---|---|
| Type 1 (bare-metal) | Directly on hardware | ESXi, Hyper-V, KVM | Servers/data centers |
| Type 2 (hosted) | On top of a host OS | VirtualBox, VMware Workstation | Desktops/labs |
📌 VMs vs. Containers¶
| Virtual Machine | Container | |
|---|---|---|
| Includes | Full guest OS | App + dependencies (shares host kernel) |
| Size / startup | Large / slow | Small / fast |
| Isolation | Strong (separate OS) | Lighter (process-level) |
| Example | VMware VM | Docker container |
Containers are lighter and faster because they share the host OS kernel instead of each running a full OS.
📌 Network Function Virtualization (NFV)¶
NFV runs network functions — firewalls, routers, load balancers — as software/VMs on standard servers instead of dedicated appliances, improving flexibility and cost.
📌 Virtual Networking¶
VMs connect via virtual switches (vSwitches) and virtual NICs inside the hypervisor, which then bridge to the physical network.
Tip
Key idea — Hypervisors run VMs: Type 1 on bare metal (servers), Type 2 on a host OS (desktops). Containers are lighter, sharing the host kernel. NFV turns network appliances into software.
See also: Cloud Service Models, Remote Access Methods
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