1. NETE4631 SOA and Cloud Computing Service Models
Lecture Notes #4

2. Cloud computing - Recap(1)

3. Cloud Enabling Technologies - Recap(2)HW
(Clusters of) servers in data centers SW
Network (WAN)
Web browser – HTTP (HTML, DHTML)
Web service (in this class)
Data
People
Virtualization
Utility +
Grid Computing

4. Lecture Outline Service-Oriented Architecture (SOA)
Service-Oriented Computing (SOC)
SOC state-of-the-art and research challenges
Some of the implementation technologies
SOA VS Cloud
Service and deployment models

5. Architecture of a Web Retail System
Source: Grady Booch’s site: Rozanski, N. and Woods, E. Software Systems Architecture. Reading, Massachusetts: Addison-Wesley, 2005, p. 96.

6. Service-Oriented Architecture (SOA)
“A service-oriented architecture (SOA) is an application framework that takes everyday business applications and breaks them down into individual business functions and processes, called services. An SOA lets you build, deploy, and integrate these services independent of applications and the computing platforms on which they run.” –IBM“
Service-Oriented Architecture is an approach to organizing information technology in which data, logic, and infrastructure resources are accessed by routing messages between network interfaces.” –Microsoft

7. Service-Oriented Architecture (SOA) (2)
An SOA is “a set of components which can be invoked, and whose interface descriptions can be published and discovered.” –W3C.
“A paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains. It provides a uniform means to offer, discover, interact with and use capabilities to produce desired effects consistent with measurable preconditions and expectations.” –The OASIS Group

8. Motivators of SOA Increasing nature of distributed systems
Heterogeneity of systems and computing environments
Dynamics of operating environments
Transparency of communication infrastructure details
Process-orientation requires multiple services

9. Service-Oriented Computing
Development of rapid, low cost, & interoperable systems that are independent of programming languages and operating systems
Help create compound solutions using legacy systems and enterprise information systems exposed as loosely coupled services residing on remote networks
Organization can programmatically offer their business processes over the Internet or on various networks

10. What is a service?
A service is an implementation of a well-defined piece of business functionality, with a published interface that is discoverable and can be used by service consumers when building different applications and business processes.

11. Principles of Identifying Services
A Service should:
Represent a tangible business concept
Consist of a series of organization-wide analysis, where a process can decompose into several small set of processes
Reusable processes -within or outside an organization, identify possible inputs and outputs (should be generic) for these business processes
Identify dependencies among services and their impact on internal or external to a system

12. Web Services
They look for suitable services in a directory, e.g., UDDI
Analyze the specifications of the potentially relevant services by reading something like WSDL
Select the most relevant service and get it do something of value to the service consumer using something like SOAP
Exploit the standards (e.g., WS-* standards) for ensuring quality attributes security and reliability.

13. Service Provision and Consumption

14. Enterprise Service Bus
Provide location transparent routing and addressing for service communication; service addressing and naming administration, support at least one messaging paradigm and transport protocol
Support effective service integration through multiple integration mechanisms, including connectors, web services, messaging, and adaptors

15. Enterprise Service Bus (2)
Provides an open service messaging and interfacing model in order to isolates implementations from routing services and transport protocols, and allows implementations to be substituted

16. Enterprise Service Bus (ESB)
Source:Dodani, M., From Objects to Services: A Journey in Search of Component Reuse Nirvana, JOT, 3(8), 2004.

17. Common Design Principles
Services are reusable
Business functionalities exposed as services are designed with the intention of reuse whenever and where they are required
Services share a formal contract
Services interact with each other through a formal contract which is shared to exchange information and terms of usage

18. Common Design Principles (2)
Services are loosely coupled
Services are designed as loosely coupled entities able to interact while maintaining their state of loose coupling.
Services abstract underlying logic
The business logic underpinning a service is kept hidden from the outside world. Only the service description and formal contract are visible for the potential consumers of a service

19. Common Design Principles (3)
Services are composable
Services may composed of other services. Hence, a service’s logic should be represented at different levels of granularity and promotes reusability and the creation of abstraction layers.
Services are autonomous
A service should be independent of any other service

20. Common Design Principles (4)
Services are stateless
A service shouldn’t be required to maintain state information rather it should be designed to maximize statelessness
Services are discoverable
A service should be discoverable through its description, which can be understood by humans and service users. A service can be discovered by the use of a directory provider, or, implementation mechanism or hard-coded address

21. Common Design Principles (5)
Services have a network-addressable interface
A service should be invoked from the same computer or remotely –through a local interface or Internet
Services are location transparent
A service should be discoverable without the knowledge of its real location. A requestor can dynamically discover the location of a service looking up a registry
The core principles are autonomy, loose coupling, abstraction, formal contract

22. SOC: State-of-the-Art and Research Challenges
Service Foundation
Dynamically reconfigurable runtime architectures, End-to-end security solutions, Infrastructure support for data and process integration, Semantically enhanced service discovery
Service Composition
Composability, Dynamic and adaptive process, QoS-aware service composition, Business-driven automated compositions
Service Management and Monitoring
Self-Configuration and adaptation, Self-healing, Self-optimization, Self-protecting
Service Design and Development
Engineering service-based systems, Gap analysis techniques, Service versioning and adaptivity, Service governance

23. Implementation Technologies
XML Web Services
Common Object Request Broker Architecture (CORBA)
Java Remote Method Invocation (RMI)
.Net Remoting
Message Orietned Middleware (MOM) –IMB’s MQSeries, Microsoft Message Queuing (MSMQ), or Java Message Service
TCP/IP

24. Protocol Stack for SOA

25. Service Orchestration or Choreography

26. SOA and Cloud Do with practicing SOA Do SOA with leveraging Cloud
SOA is more holistic and strategic – deal with the complete enterprice including business drivers. Cloud – more tactical (instance of archtecture) – is a way of solving a problem

27. SOA leveraging Cloud SOA on demand
SOA can learn from cloud in (1) service design from large vendor and (2) service expandability (resouces) to support scallability issue that is not addressed in SOA

28. Cloud architecture model

29. Service and Deployment Models

30. Categories of Cloud Services

31. Infrastructure as a Service (IaaS)
Also known as Datacenter as a Service
Hardware virtualized in cloud based on demand
Service vendor owns equipment
A user creates virtual hardware for deploying applications or platform for developing application
Incredibly disruptive technology for utility computing
Fundamental unit of virtualized client is workload
A typical eCommerce system will have
Web server, Application server, File server, Database, Transaction engine, & other types of servers

32. IaaS: Pods, Aggregation, & Failover

33. Platform as a Service (PaaS)
A software environment that provides development and deployment environment and tools (e.g., application development, database development, storage, testing, etc.)
A platform can be specific to a language, application framework, or other constructs
PaaS system must also support the development of interfaces with technologies like HTML, JavaScript
Vendor lock-in is quite considerable –migrating a python application written for Google’s API

34. PaaS Model Services A set of technologies and tools
Collaboration –Multiple people can work together
Data management –Accessing and using data
Instrumentation, performance, and testing
Storage service with the same vendor or a third party
Transaction management services or brokerage services for managing transactions

35. An Integrated Lifecycle Platform
Virtual machine and operating system (IaaS)
Data design and storage
Development environment with relevant APIs
Middleware
Testing and optimization tools
Other tools and services as appropriate

36. Storage as a Service

37. Database as a Service

38. Information as a Service

39. Process as a Service

40. Software as a Service (SaaS)
Also known as application as a Service
Any application that is delivered over the platform of the web.
Major Categories of SaaS
Line of Business Services
Business solutions offered to companies based on subscription fee, e.g., CRM and Supply Chain Management
Customer-oriented Services
Services offered to general public, most free
Business models are based on advertising revenue (e.g., You Tube)
Sw or applications hosted in the internet and available accessed through browser / replacing physical software on the browser
SaaS – complete services offering – hardware- software – solution – replaing shring wraped sw deploying in the internet
Excepted for the interaction to the software, all other details are abstracted away.
Hardly to customize except salesforce and Quicken that provide API such as changing the security models data scema worklow characteristics

41. SaaS Characteristics
Browser based on demand availability, different kinds of licenses
Responsibilities -Vendors and Users
Cheaper compared with shrink-wrapped versions, lowering entry barriers
Compatibility among all users’ software
Shared data model for multiple users through single instance, multi-tenancy
Reduce distribution and maintenance costs – cheaper that shrink-wrap
Upgraded easily
All users will have the same version of sw
Support multiple users

42. Potential Advantages
Faster time to market and improved productivity with lower cost
Eliminate the need to install and maintain
Fast upgrades of new features and patches
Provision of application developed using very mature processes and practices
Companies can focus on core business

43. Potential Disadvantages
Maturity in designing multi-tenant applications
Required cultural and organizational changes
Difficult to translate business models
Some applications not suitable for this model
Need to comply with the vendors’ constraints
Migration can be problematic

44. Motivating Factors Popularity
Both Software Vendors and Enterprizes Like it
Each of them has different reasons –Why???
Plenty of SaaS Platform
Each big software vendor (such as Oracle and Microsoft) is developing several SaaS platforms
SaaS and SOA
Popularity of SOA helps migration to SaaS
SOA provides a design framework for low cost development with high quality systems
Economic Impact

45. Some of the SaaS Providers
Intuit
Quikbooks and Quikbook online
Phone and Blackberry capabilities
Google
Google Apps (Standard and Premier Edition)
Microsoft
Microsoft Office Live Small Business & Office 365
IBM
Blue Cloud

46. Other Services Integration as a Service Security as a Service
Governance/ Management as a Service
Testing as a Service

47. Comparing cloud services
Modified from Building the cloud Virtualized Optical WAN

48. References Chapter 3,4,7 and 13 of the book by Sosinsky, B., 2011.
Papazoglou, M., Traverso, P., Dustdar, S., Leymann, F., 2007, Service-Oriented Computing: State of the Art and Research Challenges, IEEE Computer, 40(11), pp
Cloud Computing and SOA Convergence in your Enterprise, Linthicum, D., S.