Contents

Preface

Why This Book

About the Author

1  Introduction

1.1  SaaS Deployed and Provided from Cloud Environment

1.2  Software Solution

1.3   ‘Software Architecting’ is Different from ‘Software Designing’

1.4   TOGAF, ABBs, SBBs and Building Blocks

1.5  Cloud SaaS – An Evolution and SaaS Business Models

1.5.1  Mainframe Leasing Model

1.5.2  Conventional, On-Premise Installed Model

1.5.3  Hosted Model of 1990s

1.5.4  Cloud Model: (SaaS Provided from Cloud Environment)

1.6  SaaS Provided from Cloud Environment vs Hosted Model

1.7  Enterprise Models for SaaS Consumption

1.7.1  Modelling Enterprises (for the Sake of Providing Solutions)

1.7.2  Bigger Enterprises and Verticals

1.7.3  Small- and Medium-sized Enterprises

1.7.4  Long Tail

1.8  Summary

2  Architecting Methods for Cloud SaaS Software – Solutions or Products

2.1  Introduction

2.2  Cloud SaaS Solution Addressing Business Capabilities of SMEs

2.3  Adopting TOGAF’s ADM Phases for Cloud SaaS Solution

2.3.1  Phases – Preliminary Phase to Phase A–D

2.3.2  Phase E: Opportunities and Solutions

2.3.3  Remaining Phases in ADM

2.4  Agile Architecting Method

2.4.1  Requirements Collection and Identification of ABBs

2.4.2  Architecting by Employing Techniques from TOGAF

2.5  Summary

3  How Do Hypervisors Work? How Does IaaS Function?

3.1  Introduction

3.2  Hardware Virtualization

3.3  Auto-Provisioning

3.4  Data Centre Rack Systems

3.5  Scaling through Software Architecture or Hardware

3.6  Motivation or Need for Scalable Architecture

3.7  Scalable Architecture (of Software)

3.8   Concept of Load Balancer

3.9  Auto-Scaling

3.10  Summary of Capabilities of Hypervisors

3.11  A Simple Model of Infrastructure as a Service (IaaS)

3.12  Example Case Situations

3.13  Summary

4  Architecting Software Solutions for Public IaaS Cloud (without SaaS)

4.1  Introduction

4.2  The Method in Brief

4.2.1  Identifying Minimum Deployment Hardware Configuration for each SBB

4.2.2  Calculating IaaS Infrastructure Configuration

4.3   Digital Communication Platform

4.4  Approach to Realization

4.5  Realization of the Envisaged Solution Architecture

4.6  Architectural Considerations

4.7  Mapping Deployment Architecture into Public IaaS Cloud

4.8  Summary

5  Characteristics of Cloud SaaS Software

5.1  Introduction

5.2  Multi-Tenancy

5.3  Customization

5.3.1  Web Tier: User Interface

5.3.2  Business Tier

5.3.3  Data Tier

5.3.4  Reports

5.3.5  Abilities to Choose Functions at Fine Granular Level

5.4  Scaling (Auto-Scaling and Auto-Provisioning)

5.5  Operational and Billing Support Services

5.6  Software Upgrades and Maintenance

5.7  Maintenance of Database

5.8  Efficient Multi-Tenancy

5.9  SaaS Architecture is Unique

5.10  Summary

6  Cloud Compatibility Measure

6.1  Introduction

6.2  Motivation to Come Up with Cloud Compatibility Measure

6.3  Definition of ‘Cloud Compatibility’

6.4  SaaS (Solutions) Maturity Model

6.5  SaaS Maturity Continuum Scale

6.6  Cloud Compatibility Measure

6.6.1  Procedure to Set Up the ‘Cloud Compatibility Measuring Scale’

6.6.2  Ideal Values for Characteristics

6.6.3  Case Study – Measures for Two Products of Similar Functionalities

6.7  Combined Discussion about All the Three ‘Cloud Compatibility Measures’

6.8  Summary

7  Architecting SaaS Solutions for Cloud Using Semi-Cloud Compatible SBBs

7.1  Introduction

7.2  Case Study

7.2.1  Introduction to Case Study

7.2.2  Description of Customer

7.2.3  Customers’ Requirements

7.2.4  Solutions Implications and Constraints

7.2.5  Case Model

7.3  Architecting Solution

7.3.1  Building Business Capabilities for a Group of Enterprises

7.3.2  Calibrating COTS against Cloud Compatibility Criteria

7.3.3  Key Challenges and Solutions in Finalizing SBBs

7.3.4  Security Requirements and Solutions to the Final Solution

7.4  Summary of Cloud-Based SaaS Solution

7.4.1  Deployment Architecture for Minimum Usage

7.4.2  Evolving Deployment Architecture

7.4.3  Size Software for Scalability

7.4.4  Determining Scaling Algorithms

7.5  Other Routine Steps for Implementing the Solution

7.6  Less Cloud-Ready Software Costs More for Per-User/Time

7.7  Summary

8  Architecting Cloud SaaS Solutions with Cloud Non-Compatible Products

8.1  Introduction

8.2  Classification of Solutions Using Not-at-All Cloud Compatible Products

8.3  Some General Strategies

8.4  Case Study

8.4.1  Use Case 1

8.4.2  Use Case 2

8.4.3  Some Common Observations

8.4.4  Solution Description

8.5  Summary

9  Architecting Cloud Compatible SaaS Software Products

9.1  Introduction

9.2  Cloud SaaS Product Architecture Development Methodology

9.3  Drivers Influencing Architecture of Cloud SaaS Products

9.4  Characteristics Required for Cloud-SaaS-Products’ Architecture

9.5  Selection of Basic Architecture for Cloud Compatible SaaS Product

9.6  Starting Points for Architecting Projects

9.6.1  Starting from CCRA for SaaS

9.6.2  Starting from Functional Requirements of Cloud SaaS Product

9.7  Distributed Applications Architecture

9.7.1  Tier-Wise Specific Points Relevant to Architecture of Cloud SaaS

9.7.2  Architecting to Scale the Application

9.7.3  Service Orientation of Entire Product Architecture

9.8  Identity and Access Management

9.9  Transaction-less vs Transaction-intensive Products

9.10  Efficient Multi-tenancy

9.11  Infrastructure Softwares’ Architectures for SaaS Solutions

9.12  Deployment Architecture Basics for Cloud SaaS Products

9.13  Future Direction

9.14  Summary

10  Cloud Computing Reference Architecture

10.1  Introduction

10.1.1  Review Bias

10.1.2  What Does CCRA Bring to Table for Solution Architects?

10.2  Cloud Computing Architectures Are Service-Oriented Architectures

10.2.1  Important Aspects of Cloud (SaaS) Services

10.2.2  Cloud Reference Architecture Derives Experience from SOA in Addressing these Aspects

10.3  A Quick Summary of the SOA RA

10.4  Using the SOA RA with the CCRA

10.5  CCRA – Architecture Overview Diagram

10.5.1  Roles of CCRA

10.5.2  Architectural Elements for Each of These Three Major Roles

10.6  Architectural Principles and Related Guidance

10.7  Comparison of CCRAs of IBM^TM, Microsoft^TM and HP^TM[25]

10.8  Summary

11  Architecting for Security in Cloud SaaS Software

11.1  Introduction

11.2  Segments of Security

11.3  Security Architecture for Cloud SaaS

11.4  Security as an Aspect

11.5  Building Security within SaaS Software: Some Implementation Tips

11.6  Summary

Abbreviations

References

Keyword Taxonomy Through Semantic Tree

Key Words Taxonomy