CLOUD COMPUTING

CONTENTS

ArrivalCharactersDefinitionMeritsCharartersticsWorkflowsWfmsWorkflow engineWorkflows levels & categories

INTRODUCTION

ARRIVAL :

Parrallel computingDistributed computingGrid computingPublic computing SAAS

CHARACTERS :

Virtualization : nothing to do with physical platforms

Distribution : refers to the physical node which the computation uses is distributed

Dynamically extendibility : refers to through the dynamic extension virtualization level, then achieves to above applies carries on the expansion the goal.

Cloud Computing :

• Delivering applications or services in on-demand environment

Hundreds of thousands of users / applicationsSystems should be fast, secure and availableIntelligent infrastructure:

TransparencyScalabilityMonitoringSecurity

All services and associated data

Merits :

It provides a mandatory application program environment.

a distributed foundation establishment, and monitor the distributed system, to achieve the purpose of efficient use of the system.

it integrates the history data and present data to make the collected information more accurate and provide more intelligent service for users and enterprises.

cloud computing is easy to extend, and has an simple management style.

supports for SAAS(software as a Service).

The aim of application of cloud computing is to combine all the resources, and let anyone can use it.

Charaterstics of cloud computing :Ultra large scaleVirtualizationHigh reliabilityVersatilityHigh extendibilityOn demand serviceExtremely inexpensive

WORKFLOW :

“The automation of a business process, in whole or parts, where documents, information or tasks are passed from one participant to another to be processed, according to a set of procedural rules “

Workflows :

Operational aspect of a work procedure: how tasks are structured, who performs them, what their relative order is, how they are synchronized, how information flows to support the tasks and how tasks are being tracked.

Workflow Management System (WFMS)“A system that defines, creates and manages

the execution of workflows through the use of software, running on one or more workflow engines, which is able to interpret the process definition, interact with workflow participants and, where required, invoke the use of IT tools and applications.”

Workflow Engine“A software service or "engine" that provides

the run time execution environment for a process instance.”

WORKFLOWS LEVELS :Inside domain

One unit/organization/Virtual Organization

Level Up AboveMultiple Virtual Organizations

Global Model More dynamic More Grid …Global ModelGlobal ProcessPeer-To-Peer

Orchestration …Choreography …

Categories of workflows :

CollaborativeProductionAd HocAdministrative

Workflow Lifecycle :Design

Typical workflow is graph orientedLanguage: how expressive is workflowGUI: Visual Service Composition Environment

DeploymentWorkflow Description is sent to Workflow Engine Possibly validated and compiled

ExecutionWorkflow Engine enacts Workflow Description

MonitoringEvents reflecting from workflow and services execution

Refinement

Workflow Usage Concerns :Constructs supported

Expressiveness of Programming LanguageEase of creation and modification by non

programmers (GUI)ExtensibilityEase of IntegrationSupport for StandardsSupport for Web ServicesSupport for Grid, GT2, OGSIEase of Use (Very subjective …)Status, AvailabilityLicensing, Price

Workflow Mangement :

An activity is a discrete step in a business process (workflow).

Activities range from calling a remote service to perform a task, e.g. calculating taxes, performing currency conversions, looking up inventory, to custom-defined services.

Activities are orchestrated together in a workflow in BizTalk using XOML (eXtensible Object Markup Language).

Other languages BPEL, ebXML, XPDL etc.