Cloud Computing Services: Fundamentals, Models, and Architecture

Course Overview and Evaluation Scheme

• Course Structure:

  • Module 1: Introduction to Cloud Computing ($6\text{H}$)
  • Module II: Cloud Computing Services ($7\text{H}$)
  • Module III: OpenStack Cloud Platform & Serverless Computing ($9\text{H}$)
  • Module IV: Cloud Ecosystem ($9\text{H}$)
  • Module V: Cloud Security and Tools ($8\text{H}$)
  • Module VI: Identity Access Management & Cloud Security

• Evaluation Scheme:

  • End Semester Exam: $60$
  • Midterm Test: $20$
  • Continuous Assessment: $20$

• Continuous Assessment Components (Best $2$ of $3$ allocated for total of $20$ marks):
  • Presentation: $10$
  • Case Study: $10$
  • Assignment: $10$

Core Requirements and Resource Management

• Enterprise Architecture Evolution: Single module program $\rightarrow$ Service domain (e.g., finance, business) $\rightarrow$ Application level $\rightarrow$ Enterprise level application.
• Primary Resource Pillars:
  • Compute power for processing (front-end interactive screen/GUI, main server processing, back-end database management).
  • Space for storage (physical media: RAID, hard disk, tape drives).
  • Bandwidth for communication (networking hardware and protocols across LAN, MAN, WAN).
• System Reliability Metrics:
  • Mean Time To Repair ($\text{MTTR}$): Duration spent from system failure to full repair.
  • Mean Time Between Failures ($\text{MTBF}$): Operating duration between failures.
  • Operational requirement: $\text{MTBF} \gg \text{MTTR}$.
• Information Life Cycle:

• Stages: Identify $\rightarrow$ Acquire $\rightarrow$ Migrate $\rightarrow$ Archive $\rightarrow$ Destroy.

Key Features of Cloud Computing

• Standardization: Uniform hardware and software resources to ensure plug-and-play capability and minimize interface friction.
• Automation: Centralized control mechanisms to reduce manual management and limit human error.
• Abstraction: Internal physical infrastructure layouts and operational details are hidden from users.
• Virtualization: Abstracts physical resources to present customized virtual environments (virtual disk, virtual OS, virtual network, virtual memory).

Cloud Service Models (SPI Model)

• Infrastructure as a Service (IaaS):
  • Provides rented physical compute power, storage space, and network bandwidth on a pay-per-use model bound by a Service Level Agreement (SLA).
• Platform as a Service (PaaS):
  • Delivers software development platforms, testing, debugging, and execution environments without requiring platform software license purchases.
• Software as a Service (SaaS):
  • Delivers turnkey hosted applications to end users along with deployment, billing, maintenance, and update infrastructure.
• Secondary Services (XaaS):
  • Developer-created applications hosted on cloud infrastructure offered as extended services (e.g., Database as a Service, Storage as a Service, Security as a Service, Collaboration as a Service, Backup as a Service, Disaster Recovery as a Service).

Cloud Deployment Models and Cloud Cube Model

• Deployment Models:
  • Private Cloud: Accessible exclusively by authorized internal personnel.
  • Public Cloud: Infrastructure open to all users over public networks.
  • Community Cloud: Shared resource pooling among specific organizations with shared requirements.
  • Hybrid Cloud: Combined private and public cloud deployment connected via secure interfaces.
• Cloud Cube Model (4 Dimensions):

• Physical Location: Internal vs. External
• Ownership: Proprietary vs. Open
• Security Perimeter: Perimeterised vs. De-perimeterised
• Sourcing: Insourced vs. Outsourced

Cloud Ecosystem Stakeholders

• Cloud Owner / Cloud Manager: Manages infrastructure, handles capacity planning, requires resource provisioning features.
• Cloud Administrator: Oversees billing, system control, server, and network administration.
• Vendors: Supply raw software and hardware resources adhering to standardization.
• Cloud Service Provider: Captures user requirements, interfaces with vendors, and delivers virtualization.
• Application Developers: Build IaaS, PaaS, and SaaS applications leveraging virtualization.
• End User: Utilizes SaaS-hosted applications.

Advantages and Disadvantages of Cloud Computing

• Advantages:
  • On-demand self-service, broad network access, dynamic resource pooling, and rapid elasticity (scaling up/down).
  • Measured service (usage tracking, auditing, and reporting) on a strict pay-per-use basis.
  • Reduced infrastructure costs, multitenancy efficiency, vendor independence, Bring Your Own Device (BYOD) adaptability, and single sign-on (SSO).
  • Service Level Agreement (SLA) guarantees for trust and uptime.
• Disadvantages:
  • Potential downtime due to total dependency on internet connectivity.
  • Risk of vendor lock-in and limited administrative control over cloud infrastructure.
  • Data security and privacy concerns when managing sensitive records via third parties.
  • High initial operational setup costs for cloud service providers and exposure of unmonitored network nodes to security vulnerabilities.