Chapter 5: Cloud Computing

5.1 Introduction

Cloud computing is a transformative technology that enables on-demand access to a shared pool
of configurable computing resources. It provides businesses with the ability to scale, innovate, and
reduce costs by using remote servers and services over the internet.

5.2 Cloud Computing Shares Characteristics

Cloud computing exhibits several key characteristics:

 On-Demand Self-Service: Users can provision resources as needed without requiring

human intervention from the service provider.

 Broad Network Access: Services are accessible over the network through standard
mechanisms, allowing various devices to connect.

 Resource Pooling: Providers pool resources to serve multiple customers, dynamically

allocating and reallocating resources according to demand.

 Rapid Elasticity: Resources can be quickly scaled up or down to meet changing

workloads.

 Measured Service: Resource usage is monitored, controlled, and reported, providing

transparency for both the provider and customer.

5.3 Service Models

Cloud computing offers several service models, each catering to different business needs:

5.3.1 Infrastructure as a Service (IaaS)

 IaaS provides virtualized computing resources over the internet. Users can rent
infrastructure like servers, storage, and networking.

 Advantages:

o Flexibility to scale resources based on demand.

o Reduced capital expenditures as hardware is managed by the provider.

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  Disadvantages:

o Users are responsible for managing applications, data, and operating systems.

 Example: Amazon Web Services (AWS) EC2 allows businesses to run virtual machines
and scale resources dynamically.

5.3.2 Platform as a Service (PaaS)

 PaaS provides a platform allowing developers to build, deploy, and manage applications
without worrying about the underlying infrastructure.

 Advantages:

o Simplifies the development process by providing built-in tools and services.

o Accelerates time to market for new applications.

 Disadvantages:

o Limited control over the underlying infrastructure.

 Example: Google App Engine enables developers to build and host applications in
Google’s data centers.

5.3.3 Software as a Service (SaaS)

 SaaS delivers software applications over the internet on a subscription basis, eliminating
the need for installation and maintenance.

 Advantages:

o Accessible from any device with internet connectivity.

o Automatic updates and maintenance handled by the provider.

 Disadvantages:

o Limited customization options for users.

 Example: Microsoft 365 provides a suite of productivity applications, including Word and
Excel, accessible via the web.

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5.3.4 Mobile "Backend" as a Service (MBaaS)

 MBaaS provides mobile app developers with cloud-based backend services, facilitating the
integration of various features like user authentication and push notifications.

 Advantages:

o Speeds up mobile app development by providing pre-built backend services.

o Reduces the need for extensive server-side programming.

 Disadvantages:

o Dependency on the MBaaS provider for backend functionality.

 Example: Firebase by Google offers a comprehensive backend solution for mobile

applications, including real-time databases and authentication.

5.3.5 Serverless Computing

 Serverless computing allows developers to build and run applications without managing
servers. The cloud provider automatically provisions and manages the infrastructure.

 Advantages:

o Cost-effective since users pay only for the compute time used.

o Simplifies deployment and scaling of applications.

 Disadvantages:

o Potential vendor lock-in and limited control over the execution environment.

 Example: AWS Lambda allows users to run code in response to events without
provisioning servers.

5.3.6 Function as a Service (FaaS)

 Definition: FaaS is a subset of serverless computing where developers deploy individual

functions that are executed in response to specific triggers.

 Advantages:

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 o Granular control over application logic.

o Event-driven execution enables efficient resource usage.

 Disadvantages:

o Complexity in managing multiple functions and their interactions.

 Example: Azure Functions enables developers to run event-driven code without managing
servers.

5.3.7 Software Defined Systems Support for Cloud Computing

 Definition: Software-defined systems abstract hardware resources, allowing for more agile
and flexible cloud environments.

 Advantages:

o Simplifies management through automation and orchestration.

o Increases resource utilization and efficiency.

 Disadvantages:

o Requires a shift in mindset and training for IT staff.

 Example: VMware’s vSphere enables the management of virtualized data centers and
cloud environments.

5.4 Deployment Models

Cloud computing has transformed how organizations deploy and manage their IT resources.
Various deployment models cater to differing needs, offering flexibility, security, and cost-
effectiveness. Below is a comprehensive overview of the primary deployment models, examples,
and key considerations for each.

5.4.1 Private Cloud

 Definition: A private cloud is exclusively used by a single organization, providing a

dedicated environment for its applications and data.

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  Advantages:

Enhanced Security: With dedicated resources, organizations can enforce strict

security protocols.

Customization: Tailored infrastructure to meet specific business requirements.

Regulatory Compliance: Easier to comply with industry standards and regulations

(e.g., HIPAA, GDPR).

 Disadvantages:

o Higher Costs: Significant initial investment in hardware and ongoing maintenance.

o Management Complexity: Requires dedicated IT staff for management and

maintenance.

 Example: A large bank implements a private cloud to manage sensitive financial data
while ensuring compliance with financial regulations.

 Considerations:

o Cost: Higher initial investments for hardware and ongoing maintenance.

o Management Complexity: Requires dedicated IT staff for management and

maintenance.

5.4.2 Public Cloud

 Definition: A public cloud is owned by third-party providers and offers resources and
services to multiple organizations over the internet.

 Advantages:

Cost Efficiency: Pay-as-you-go pricing helps minimize costs.

Scalability: Easily scale resources up or down based on demand.

Minimal Maintenance: The cloud provider handles maintenance and upgrades.

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  Disadvantages:

o Security Risks: Greater exposure to data breaches and vulnerabilities.

o Limited Control: Less customization and control over infrastructure.

 Example: A small startup utilizes Google Cloud Platform to host its applications,
benefiting from low costs and rapid scalability.

 Considerations:

o Security Risks: Data stored in a public cloud may be more vulnerable to breaches.

o Less Control: Limited customization options compared to private clouds.

5.4.3 Hybrid Cloud

 Definition: A hybrid cloud combines private and public clouds, enabling data and
applications to be shared between them.

 Advantages:

Flexibility: Organizations can choose where to run workloads based on sensitivity

and cost.

Optimized Costs: Use public cloud for non-sensitive operations while keeping
critical data in a private cloud.

Disaster Recovery: Improved resilience with multiple environments for backup

and recovery.

 Disadvantages:

o Integration Challenges: Complexity in ensuring seamless communication

between private and public environments.
o Management Overhead: Requires effective management strategies for both
environments.
 Example: A retail company maintains customer data in a private cloud while using public
cloud resources for seasonal marketing campaigns.

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  Considerations:

o Integration Challenges: Ensuring seamless communication between private and

public environments can be complex.

o Management Overhead: Requires effective management strategies for both

environments.

5.4.4 Community Cloud

 Definition: A community cloud is shared among several organizations with common

concerns, such as security, compliance, or performance needs.

 Advantages:

Cost Sharing: Organizations can share infrastructure costs, reducing expenses.

Collaborative Innovation: Facilitates collaboration on shared projects and

initiatives.

Tailored Solutions: Designed to meet specific industry requirements.

 Disadvantages:

o Governance Complexity: Requires clear governance models to manage shared

resources.

o Resource Allocation Conflicts: Potential disputes over resource usage among

organizations.

 Example: Several universities collaborate to create a community cloud for research data,
ensuring compliance with educational regulations.

 Considerations:

o Governance Complexity: Requires clear governance models to manage shared

resources.

o Resource Allocation: Potential conflicts over resource usage among different

organizations.

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5.4.5 Distributed Cloud

 Definition: A distributed cloud extends public cloud services to multiple physical

locations, offering a decentralized approach to resource management.

 Advantages:

Reduced Latency: Resources closer to end-users improve response times.

Data Sovereignty: Helps organizations comply with local data regulations by

keeping data within specific jurisdictions.

Increased Resilience: Redundancy across locations enhances reliability.

 Disadvantages:

o Management Complexity: Coordinating resources across various locations can be

challenging.

o Potential Higher Costs: May incur additional costs for data transfers and
management.

 Example: A global media company uses a distributed cloud to deliver content efficiently
to users worldwide, minimizing latency.

 Considerations:

o Management Complexity: Coordinating resources across various locations can be

challenging.

o Potential Costs: May incur higher costs for data transfer and management.

5.4.6 Multicloud

 Definition: A multicloud strategy involves using multiple cloud services from different
providers to meet various business needs.

 Advantages:

Avoiding Vendor Lock-In: Organizations can choose the best services from
different providers.

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 Flexibility: Tailor cloud services to specific workloads and performance needs.

Improved Reliability: Redundancy across multiple providers can enhance uptime

and reliability.

 Disadvantages:

o Integration Complexity: Managing multiple cloud environments can complicate

operations.

o Cost Management Challenges: Requires careful monitoring to avoid unexpected

expenses.

 Example: An enterprise utilizes Microsoft Azure for development, Amazon Web

Services for hosting, and IBM Cloud for machine learning services.

 Considerations:

o Integration Complexity: Managing multiple cloud environments can complicate

operations.

o Cost Management: Requires careful monitoring to avoid unexpected costs.

Key Considerations for Cloud Deployment

 Security: Understand the security implications of each model. Implement robust measures
to protect data, especially in public and multicloud environments.

 Compliance: Stay informed about relevant regulations that may affect data storage and
processing, ensuring adherence to industry standards.

 Cost Management: Regularly analyze cloud spending to optimize costs and avoid
overspending, especially in public and hybrid models.

 Performance Needs: Assess the performance requirements of applications to determine

the most suitable cloud model.

 Vendor Lock-In: Consider strategies to mitigate dependency on a single vendor,

particularly in public cloud environments.

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Summary

Cloud computing provides various service models tailored to different business needs, from
infrastructure to software delivery. Each model has its unique advantages and challenges, making
it essential for organizations to evaluate their specific needs, compliance requirements, and budget
constraints. By understanding these models and considerations, businesses can effectively used
cloud technology for enhanced efficiency, security, and innovation.

Reference
Software Defined Systems: Sensing, Communication and Computation (SpringerBriefs in Computer
Science) 1st ed. 2020 Edition by Deze Zeng, Lin Gu , Shengli Pan , Song Guo (Text BOOK)

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