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SIKSHAPATH Latest Articles

Cloud Computing Notes 101: Learn Fundamentals, Service Models, and Virtualization!

A modern 16:9 thumbnail featuring a glowing neon-blue cloud icon at the center, connected by lines to a laptop, smartphone, and server below. The background is a smooth blue digital gradient. The bold title "Cloud Computing Notes 101" appears at the top left, with the tagline "Master the Cloud" in a stylish script at the bottom center. The SikshaPath.in logo is placed in the bottom right corner, completing the professional and tech-savvy design.

Cloud Computing – Introduction


What is Cloud Computing?

NIST Definition

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

CharacteristicDescription
On-demand Self-serviceUsers can provision resources automatically, without human interaction with the provider.
Broad Network AccessServices are available over the network and accessed through standard mechanisms (e.g., web).
Resource PoolingProvider’s resources are pooled to serve multiple consumers using a multi-tenant model.
Rapid ElasticityResources can be scaled up or down quickly as needed.
Measured ServiceResource usage is monitored, controlled, and reported, providing transparency for both provider and consumer.

Diagram: Cloud Computing Model


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.

Diagram: Service-Oriented Architecture


Cloud Service Models

ModelDescriptionExamples
SaaS (Software as a Service)Use provider’s applications running on cloud infrastructure.Google Docs, Salesforce
PaaS (Platform as a Service)Deploy onto the cloud consumer-created applications using provider’s tools.Google App Engine, Heroku
IaaS (Infrastructure as a Service)Provision processing, storage, networks, and other resources.AWS EC2, Microsoft Azure
XaaS (Anything as a Service)Any IT function delivered as a service (e.g., Data as a Service, Science as a Service).Many emerging services

Cloud Stack Diagram


Cloud Deployment Models

ModelDescriptionExample Use Case
Private CloudCloud infrastructure operated solely for one organization.University research cloud
Public CloudCloud services offered to the general public by a provider.AWS, Google Cloud, Azure
Hybrid CloudCombination of private and public clouds, allowing data and applications to be shared.Enterprise with sensitive data
Community CloudShared 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).

Virtualization Stack Diagram

  • Benefits:
    • Run multiple OS on a single hardware.
    • Easier backup and recovery.
    • Efficient resource utilization.
    • Software testing and isolation.

Advantages of Cloud Computing

AdvantageDescription
Lower Computing CostNo need to buy expensive hardware/software.
Improved PerformanceAccess to high-performance resources.
Reduced Software CostsPay only for what you use; no need for individual licenses.
Instant Software UpdatesProviders handle updates and patches.
Unlimited StorageTheoretically unlimited, pay-as-you-go.
Increased Data ReliabilityData stored with redundancy and backup.
Universal AccessAccess from anywhere, any device.
Easier CollaborationMultiple users can work on shared data/applications.
Device IndependenceAccess via web browser, mobile app, or thin client.

Disadvantages and Concerns

Disadvantage/ConcernDescription
Requires Constant InternetNo access without internet connection.
Performance IssuesMay be slow or unreliable due to network or provider issues.
Limited FeaturesMay lack customization or advanced features.
Data Security & PrivacyRisk of data breaches, loss, or unauthorized access.
Data LossData may be lost if provider fails or is compromised.
Not Always Suitable for HPCMay not match high-performance computing needs.
Vendor Lock-inDifficult to migrate between providers due to proprietary APIs.
Compliance & Legal IssuesData location, privacy laws, and compliance requirements.

Cloud Storage

  • Definition: Cloud storage allows data to be stored on remote servers accessed from the internet, or “cloud.”
  • Features:
    • Data can be cached locally for performance.
    • Syncing across devices.
    • Examples: Amazon S3, Google Drive, Dropbox.

Cloud Sourcing and Economics

  • High Scale, Low Cost: Providers achieve economies of scale, offering lower prices.
  • Anytime, Anywhere Access: Services are available globally via the web.
  • Rapid Scalability: Resources can be scaled up or down as needed.
  • Service Level Agreements (SLAs): Contracts specifying performance, reliability, and availability.
  • Concerns: Performance, reliability, data security, standardization, and interoperability.

Security, Privacy, and Compliance

  • Security: Protecting data and applications from unauthorized access and attacks.
  • Privacy: Ensuring user data is not misused or exposed.
  • Compliance: Meeting legal and regulatory requirements (e.g., GDPR, HIPAA).
  • Trust: Confidence in provider’s ability to deliver promised services.

Summary Table: Cloud Computing

AspectKey Points
DefinitionOn-demand, scalable, shared computing resources via the internet
Essential FeaturesOn-demand, broad access, resource pooling, elasticity, measured service
Service ModelsSaaS, PaaS, IaaS, XaaS
Deployment ModelsPrivate, Public, Hybrid, Community
VirtualizationHypervisor, VMs, resource abstraction
AdvantagesCost, scalability, flexibility, collaboration, access
DisadvantagesInternet dependency, security, compliance, vendor lock-in
Security & PrivacyData protection, access control, compliance, trust

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