Virtualization Technologies

Exam Reviewer for Advanced Operating System and Networking

Virtualization

abstracts physical computing resources so multiple virtual environments can run on one physical system. It can virtualize CPU, memory, storage, and networking.

Virtual Machine Architecture

contains its own guest operating system and applications

hypervisor

The _____ provides the virtualization layer and manages access to the physical resources.

Hypervisor

is the software layer responsible for creating and managing virtual machines. It manages VM access to CPU, memory, storage, and network resources.

Type 1 (Bare Metal)

Directly on physical hardware

Type 1 (Bare Metal)

Typical use in enterprise servers and data centers

Type 1 (Bare Metal)

Examples are VMware ESXi, Microsoft Hyper-V, Xen, KVM

Type 1 (Bare Metal)

Often centralized

Type 2 (Hosted)

On a host operating system

Type 2 (Hosted)

Typical used in development, testing, training, desktop virtualization

Type 2 (Hosted)

Example are Oracle VirtualBox, VMware Workstation

Type 2 (Hosted)

Usually local

Server consolidation

Better resource utilization

Faster provisioning of systems

Workload isolation

Scalability

Simpler testing and recovery

Why Virtualization

Server consolidation

multiple workloads can run as VMs on shared infrastructure instead of one physical server per workload.

vCPU

RAM

Virtual disk

vNIC

Virtual Machine Resources

vNIC

Virtual network interface

Virtual disk

Storage assigned to the VM

RAM

Virtual memory assigned to the VM

vCPU

Virtual processor allocation

Creation

Management

Scaling

Destruction

VM Lifecycle

Destruction

remove VMs that are no longer needed

Scaling

adjust resources or deploy additional VMs as requirements change

Management

start, stop, configure, monitor, and maintain the VM

Creation

create a new VM and define its initial resources

Snapshot

Backup/capture a state of a VM for short-term rollback/testing.

Snapshot

Useful for testing, configuration changes, troubleshooting.

Snapshot

Depends on the original VM/disk chain.

Clone

Create a separate copy of a VM.

Clone

Useful for repeated deployments, lab environments, testing multiple systems.

Clone

Designed as a separate VM copy.

Virtual Networking

controls how VMs communicate with the Internet, the host, other VMs, and the physical LAN

NAT
Bridged

Host-only

Internal

VirtualBox Network Modes

NAT

Internet access

NAT

Often 10.0.2.0/24 in VirtualBox

Bridged

VM participates directly in LAN

Bridged

Physical LAN

Host-only

Private host <-> VM network

Host-only

Often 192.168.56.0/24

Internal

Isolated VM <-> VM network

Internal

User-defined

Resource utilization

Scalability

Isolation

Rapid provisioning

Easier management

Recovery and mobility

Enterprise Benefits

Resource contention

Management complexity

VM sprawl

Security concerns

Storage requirements

Enterprise Challenges