The document discusses concepts related to cloud computing including virtualization, service-oriented architecture, utility computing, and grid computing. It also covers cloud computing layers and deployment models such as private, public, community, and hybrid clouds. Finally, it discusses requirements engineering (RE) models that can be used for cloud computing projects, including the V-Model, Rational Unified Process (RUP), eXtreme Programming (XP), and Volere. The early 2010s cloud market was dominated by software-as-a-service (SaaS) and infrastructure-as-a-service (IaaS), especially private clouds, while platform-as-a-service (PaaS) and public clouds were less developed.
13. •
•
Private
CC
Deployment
Models
Hybrid
These services are free or offered on a payper-use model.
•
Public
A service provider makes applications,
storage, and other resources available to the
general public.
Generally, public cloud service providers like
Amazon AWS, Microsoft and Google own
and operate the infrastructure and offer
access only via Internet (direct connectivity
is not offered)
•
Shares infrastructure between several
organisations from a specific community
with
common
concerns
(security,
compliance, jurisdiction, etc.), whether
managed internally or by a third-party and
hosted internally or externally.
•
The costs are spread over fewer users than
a public cloud (but more than a private
cloud), so only some of the cost savings
potential of cloud computing are realised
Community
14. •
Infrastructure operated solely for a single
organisation, whether managed internally or
by a third-party and hosted internally or
externally.
•
Criticism: users still have to buy, build, and
manage them and thus do not benefit from
less hands-on management; lacking the
economic model that makes cloud
computing such an intriguing concept
•
A composition of two or more clouds (private,
community or public) that remain unique
entities but are bound together, offering the
benefits of multiple deployment models.
•
Hybrid cloud architecture requires both onpremises resources and off-site (remote) serverbased cloud infrastructure.
•
Drawback: Lack the flexibility, security and
certainty of in-house applications. It provides
the flexibility of in-house applications with the
fault tolerance and scalability of cloud based
services.
Public
Private
CC
Deployment
Models
Hybrid
Community
15. • Strength Points
• Challenges
Infrastructure flexibility
Faster deployment
applications and data
Reliability & Security
of
Cost control
Complexity
Costs
Regulations and legal issues
Adaptation
of
cloud
resources to real needs
Performance
Improved productivity
Migration
“The early 2010s cloud market is
dominated by software and services in
SaaS and IaaS, especially the private
cloud. PaaS and the public cloud are
further back.”
Lack of standards
Limited customisation
16.
17.
18.
19. RE models for Cloud Computing
V Model
Rational Unified
Process (RUP)
eXtreme
Programming (XP)
• Produced by the German Federal Ministry of
Internal Affairs
• Developed by Kent Beck, Ward
Cunningham and Ron Jeffries
• RE is one of the 14 activities in the V Model
• XP is an iterative and incremental agile
method
• RE Steps are:
1. Description of initial situation and
objectives
2. Drawing up functional requirements
3. Drawing up non-functional requirements
4. Establishing risk acceptance
5. Drawing up draft of life cycle and overall
system architecture
6. Analyzing quality of requirements
7. Drawing up scope of supply and acceptance
criteria.
• Offers approaches that are well
supplemented by requirements analysis.;
User Stories and the Planning Game.
Volere
• Developed by Atlantic Systems Guild
• Provides users with a systematic, structured
and very comprehensive requirements
engineering template.
• The approach is organised as follows:
1. Motivation (the purpose of the project or
product)
2. Restrictions and specifications for the
project (conditions and assumptions)
3. Functional requirements (such as Use
Case models)
4. Non-functional requirements (usability
etc.)
5. Project information (e.g., risks, costs, task
lists).
20. Unified Process Pattern
• An incremental and iterative software development process framework
• Generally referred to it as Rational Unified Process (RUP) which describes
the generic process pattern
• To avoid the confusion between it and the IBM Rational Unified Process
software, practitioners and researchers prefer to just call it UP
RUP Characteristics
Iterative and
Incremental
• The elaboration, the
construction, and the
transition phases are divided
into time-boxed iterations
• The inception phase is only
time-boxed if the project is
large
Use-Case Driven
• Use-cases or scenarios are
used to describe the
system
Risk Focused
• The most critical risks are
addressed early in the
project life cycle
Architecture
Centric
• The executable architecture
(EA) baseline, created
during the elaboration
phase, is delivered
• EA supports the key
functional as well as nonfunctional requirements
21. 1
• The
• The smallest phase
• Determines the project scope and boundary conditions
• Determines
• Outlines one or more candidate architecture
• Develops the business case for the project
• Outlines uses cases and key requirements
• Identifies risks & the preliminary schedule – cost
Identifies
2
1.
Inception
Phase
4
• The
• The system is deployed at
the customer’s side
• Any necessary system
conversions and training is
provided
4.
Transition
Phase
RUP
Lifecycle
3.
Construction
Phase
3 • The largest phase
•T
• Each iteration delivery is an executable release of the
•E
software
2.
Elaboration
phase
• Address
• Address known risk factors
• Establishes & validates the
system architecture
• Processes in this phase
include: developing use case
diagrams, conceptual
diagrams (class diagram –
basic notations only), &
package diagram
(architectural diagram)
• Implements the EA baseline
including core components
• The output is a plan
including cost and schedule
for phase 3
• Develops the common UML diagrams: activity,
sequence, collaboration, state (transition), and
interactive overview diagrams