Cloud computing is “a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.”
Key Points:
Ubiquitous: Available everywhere via the internet.
On-demand: Resources can be provisioned as needed.
Shared Pool: Resources are pooled for multiple users.
Configurable: Resources can be customized.
Rapid Provisioning: Quick allocation and deallocation.
Minimal Management: Little manual intervention required.
Pay-as-you-go: Users pay only for what they use.
Essential Characteristics of Cloud Computing
Characteristic
Description
On-demand Self-service
Users can provision resources automatically, without human interaction with the provider.
Broad Network Access
Services are available over the network and accessed through standard mechanisms (e.g., web).
Resource Pooling
Provider’s resources are pooled to serve multiple consumers using a multi-tenant model.
Rapid Elasticity
Resources can be scaled up or down quickly as needed.
Measured Service
Resource usage is monitored, controlled, and reported, providing transparency for both provider and consumer.
Diagram: Cloud Computing Model
+-------------------+ +-------------------+
| Service Users | <-----> | Cloud Provider |
+-------------------+ +-------------------+
| |
v v
[On-demand Access] [Resource Pooling]
| |
v v
[Broad Network] [Rapid Elasticity]
| |
v v
[Measured Service] [Minimal Management]
Common Characteristics of Cloud Platforms
Massive Scalability: Ability to scale resources up or down massively.
Resilient Computing: High availability and fault tolerance.
Homogeneity: Users experience a uniform environment, regardless of underlying hardware heterogeneity.
Geographic Distribution: Resources are distributed across multiple locations.
Virtualization: Abstracts physical resources into virtual resources.
Service Orientation: Services are the primary means of interaction (Service-Oriented Architecture).
Low-cost Software: Multi-tenancy and scale reduce per-user costs.
Advanced Security: Expected to provide robust security, access control, and data protection.
Service-Oriented Architecture (SOA) in Cloud
Key Components:
Service Provider: Offers services (e.g., storage, compute, applications).
Service Consumer: Uses the services.
Service Registry/Catalogue: Directory where services are published and discovered.
Analogy: Like a telephone directory (yellow pages) for services.
Cloud infrastructure operated solely for one organization.
University research cloud
Public Cloud
Cloud services offered to the general public by a provider.
AWS, Google Cloud, Azure
Hybrid Cloud
Combination of private and public clouds, allowing data and applications to be shared.
Enterprise with sensitive data
Community Cloud
Shared by several organizations with common concerns (e.g., security, compliance).
Banking sector, government
Virtualization in Cloud Computing
Definition: Virtualization is the creation of a virtual (rather than actual) version of something, such as an operating system, server, storage device, or network resources.
Key Component:Hypervisor (Virtual Machine Monitor, VMM) – software that creates and manages virtual machines (VMs).
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