functions are concerned with defining, and possibly modeling, the workflow process and its constituent activities.
Run-time control functions are concerned with managing the workflow processes in an operational environment and sequencing the various activities to be handled as part of each process.
Run-time concerns interactions with human users and IT application tools for processing the various activity steps.
3.4 Examples of Workflow Tools
Various tools are used for the workflows in cloud computing environment. In their paper, Monika Bharti and Anju Bala [15] elaborately describe different workflow tools and their respective operating system, the language they are written in, year of release, developer of the tools, description of the tools, architectural style, database used, and respective companies [16-25].
Table 3.1: Workflow tools in cloud computing.
| Tool | Language | Year | Link |
| UGENE | C++, QtScript | 12/2011 | ugene.net |
| Bonita Open Solution | Java | 01/2011 | www.bonitasoft.com |
| Google App Engine | Python, APIs, URL fetch | 2008 | cloud.google.com/appengine |
| OrangeScape | Java | 2003 | www.orangescape.com/ |
| Kaavo | Java, PHP | 2007 | kaavo.com.cutestat.com/ |
| Oozie | hpdl | 2006 | oozie.apache.org/ |
| Pegasus | Java, Perl, Python | 2003 | www.pegasuscloud.cf/ |
| YAWL | XML, XPath and XQuery | 2002 | www.yaug.org |
UGENE: It is a free open-source cross-platform bioinformatics software, which integrates a number of biological tools and algorithms, and provides both graphical user and command line interfaces. It was developed by UniPro in December 2011. Operating system used is cross-platform, C++ and QtScript is used in language background, it is based on client-server architecture and database used in UGENE is NCBI, PDB, UniProtKB/Swiss-Prot.
Bonita Open Solution: The French National Institute for Research in Computer Science developed the Bonita Open Solution in January, 2011. The business processes can be graphically modified using Bonita Studio. The processes can also be connected to other pieces of the information system to generate an autonomous business application accessible as a web form. It creates high-tech workflows and spreadsheets. Like UGENE, cross platform is used and Java is the developing language. It is based on client-server architecture and ERP, ECM database is used.
Google App Engine: Google developed Google App Engine in 2008, which allows the users to run web application. It is also in client-server pattern and the database used in App Engine is Python or Java. Windows OS is used and Python, APIs, and UrlFetch are used as languages.
OrangeScape: It is an India-based software development company with its headquarters in Chennai, India. It was founded by Suresh Sambandam, who currently serves as chief executive officer at OrangeScape. In 2002, it was named the prime technology partner for Google App Engine.
Kaavo: It provides a framework to mechanize the deployment and run-time management of applications and workloads on multiple clouds. It takes a top-down application-centric approach for deploying and managing applications in the cloud.
Oozie: It is a Java web application that runs in a Java servlet container. Oozie workflow is a collection of actions arranged in a control dependency DAG (direct acrylic graph), specifying a sequence of actions execution, specified in hPDL (a XML process definition language).
Pegasus: Ewa Deelman developed Pegasus in 2003, which is based on client-server architecture. It translates complex computational tasks into workflows. Operating system used is Linux and Windows and language used is Java, Perl, and Python.
YAWL: A new workflow language called YAWL (Yet Another Workflow Language) offers comprehensive support for the control-flow patterns and has a proper formal foundation. It also has unique support for dynamic workflow through the worklet approach. Workflows can thus develop over time to meet new and changing requirements.
3.5 Summary
This chapter has presented the architecture of cloud computing. Cloud computing architectures are essentially subdivided into cloud platform architecture (CPA) and cloud application architecture (CAA), which are linked via the cloud services available on the IT utility marketplace. This chapter also discussed the SOA concept, life cycle of SOA and integration with cloud computing. Fundamentals of the workflow concept were also presented and some workflow tools were discussed at the end of the chapter.
EXERCISES
1 Discuss the framework of cloud computing environment with suitable schematic diagram.
2 What is service-oriented architecture? Explain its characteristics.
3 State and explain the life cycle of service-oriented architecture.
4 What is workflow? How does it coordinate multiple activities in cloud computing environment?
5 Discuss the importance of workflow and state at least one work tool and its working principle.
6 Discuss the challenges of cloud computing environment.
7 What are the various reasons for cloud computing using a stateless server?
8 Provide a real-time example where SOA and cloud computing work together.
