TECHNOLOGY 

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KembaraXtra -Computer Science - Cloud Computing
This study guide summarizes key concepts of cloud computing, focusing on definitions, drivers, service models, and deployment models. It's designed for thorough understanding and exam preparation.
I. Core Concepts of Cloud Computing
A. Definition:
  • NIST Definition: Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (networks, servers, storage, applications, services) that can be rapidly provisioned and released with minimal management effort. This is the most academically accepted definition. Simply put, it's the delivery of computing services over a network.
B. Drivers of Cloud Adoption:
  • On-Demand Self-Service: Immediate access to resources, significantly increasing agility. This contrasts sharply with the traditional procurement and setup processes of on-premise hardware.
  • Scalability: Ability to easily increase capacity to meet demand.
    • Horizontal Scaling: Adding more servers.
    • Vertical Scaling: Increasing the capacity of existing servers (CPU, memory).
  • Rapid Elasticity: Dynamically scaling resources up or down based on fluctuating needs. This is closely related to scalability but emphasizes the speed and responsiveness of resource allocation.
  • Broad Network Access: Accessible via internet from anywhere.
  • Measured Service: Usage is metered, allowing for precise billing based on consumption. This promotes efficient resource management and cost optimization.
II. Cloud Service Models
This section details the four major cloud service models:
A. Software as a Service (SaaS):
  • Definition: The provider delivers a complete application to customers. Customers don't manage infrastructure; they simply use the service.
  • Examples: Google Workspace, Microsoft 365, Dropbox, Box, specialized applications like credit card processing.
  • Key Feature: Minimal to no configuration required on the customer's side.
B. Infrastructure as a Service (IaaS):
  • Definition: Customers purchase basic computing resources (compute, storage, networking) and build their own solutions.
  • Major Providers: AWS, Microsoft Azure, Google Cloud Platform.
  • Key Feature: Provides maximum control and flexibility for infrastructure management.
C. Platform as a Service (PaaS):
  • Definition: Provides a platform for running application code without managing servers. It sits between IaaS and SaaS.
  • Key Feature: Offers a balance between control (running your own code) and ease of management (no server management).
D. Desktop as a Service (DaaS):
  • Definition: Virtualized desktops accessed remotely. Enables flexible remote work arrangements.
  • Examples: Amazon WorkSpaces, on-premise DaaS solutions.
  • Key Feature: Enables accessing a full desktop environment from any device with internet access.
III. Cloud Deployment Models
This section covers the three primary deployment models:
A. On-Premises/Private Cloud:
  • Definition: Organization builds and manages its own cloud infrastructure, either internally or with a partner.
  • Rationale: Maintain control over data and resources. Not sharing infrastructure with other organizations.
B. Public Cloud:
  • Definition: Multi-tenancy model where resources are shared among many customers.
  • Key Concept: Multitenancy: Many customers share the same physical hardware. Isolation mechanisms are crucial for security and performance.
  • Challenges: Potential for performance degradation if simultaneous resource demands exceed capacity.
C. Hybrid Cloud:
  • Definition: Combines public and private cloud environments.
  • Rationale: Leverage benefits of both models – public cloud for scalability and cost-effectiveness, private cloud for sensitive data.

. Key Terms Summary

Term

Definition

Cloud Computing

Delivery of computing services over a network.

On-Demand Self-Service

Immediate access to cloud resources.

Scalability

Ability to easily increase or decrease capacity.

Elasticity

Dynamically adjusting capacity based on fluctuating demand.

Measured Service

Usage-based billing for cloud resources.

SaaS

Software as a Service (complete application provided).

IaaS

Infrastructure as a Service (basic computing resources).

PaaS

Platform as a Service (platform for running application code).

DaaS

Desktop as a Service (remotely accessed virtual desktops).

Multitenancy

Multiple customers sharing the same physical hardware in a public cloud environment.

Private Cloud

Cloud infrastructure owned and managed by a single organization.

Public Cloud

Cloud infrastructure shared among multiple organizations.

Hybrid Cloud

Combination of public and private cloud environments.

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