When orchestrating highly distributed and data-intensive Web service workflows the geographical placement of the orchestration engine can greatly affect the overall performance of a workflow. Orchestration engines are typically run from within an organisations' network, and may have to transfer data across long geographical distances, which in turn increases execution time and degrades the overall performance of a workflow. In this paper we present CloudForecast: a Web service framework and analysis tool which given a workflow specification, computes the optimal Amazon EC2 Cloud region to automatically deploy the orchestration engine and execute the workflow. We use geographical distance of the workflow, network latency and HTTP round-trip time between Amazon Cloud regions and the workflow nodes to find a ranking of Cloud regions. This combined set of simple metrics effectively predicts where the workflow orchestration engine should be deployed in order to reduce overall execution time. We evaluate our approach by executing randomly generated data-intensive workflows deployed on the PlanetLab platform in order to rank Amazon EC2 Cloud regions. Our experimental results show that our proposed optimisation strategy, depending on the particular workflow, can speed up execution time on average by 82.25 compared to local execution. We also show that the standard deviation of execution time is reduced by an average of almost 65 using the optimisation strategy.
In previous work @cite_6 @cite_11 we proposed , a proxy-based architecture based on a centralised control flow, distributed data flow model. Our prior work @cite_2 has also focused on decentralised service choreography models. @cite_4 , an architecture for of composite Web services defined in BPEL is proposed.
@cite_4 @cite_2 @cite_6 @cite_11
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Web service orchestrations-expressed in the Web service business process execution language (WS-BPEL or BPEL for short)-are a manifestation of the two-level-programming paradigm where services, i.e. the business functions used by the composite application, are composed through BPEL's control flow constructs. BPEL processes Web service orchestrations, business functions therefore can be transparently accessed remotely, allowing to build composite applications that integrate business functions provided by different partners on different locations. As of today, execution of BPEL processes, i.e. the evaluation of the processes' control flow, is performed by a central workflow engine. In certain scenarios, such as complex collaborative cross-partner interactions, this approach of centralized workflow enactment leads to "un-natural" process models; process models that are not driven by the processes' original business goal but by infrastructural or organizational reasons. In this paper, we propose an alternative approach to enacting BPEL process control flow in a distributed, decentralized manner. We present the overall process lifecycle and give a detailed description of the underlying process model. Web services make information and software available programmatically via the Internet and may be used as building blocks for applications. A composite web service is one that is built using multiple component web services and is typically specified using a language such as BPEL4WS or WSIPL. Once its specification has been developed, the composite service may be orchestrated either in a centralized or in a decentralized fashion. Decentralized orchestration offers performance improvements in terms of increased throughput and scalability and lower response time. However, decentralized orchestration also brings additional complexity to the system in terms of error recovery and fault handling. Further, incorrect design of a decentralized system can lead to potential deadlock or non-optimal usage of system resources. This paper investigates build time and runtime issues related to decentralized orchestration of composite web services. We support our design decisions with performance results obtained on a decentralized setup using BPEL4WS to describe the composite web services and BPWS4J as the underlying runtime environment to orchestrate them. Enforcing in code privacy laws, internal company rules and principles like Privacy by Design is recognized as a challenge for the IT industry. In this paper we analyze the steps required and propose a guide towards this major goal. Our proposal is to emphasize the need to overcome the limits of service orchestration and create strong privacy and security enabling architectures based on two main ideas. The first idea is to use a semantic firewall that is capable to check privacy properties for the communication between applications and cloud and between cloud's sub-systems. The second idea is to improve current SOA architectures with architectures based on executable choreographies that can be formally verified. In this paper we identify three types of executable choreographies. New types of abstraction which machines can verify and humans can trust are enabled by executable choreographies that act like truly verifiable environments for cloud applications. Information-Centric Networks place content as the narrow waist of the network architecture. This allows to route based upon the content name, and not based upon the locations of the content consumer and producer. However, current Internet architecture does not support content routing at the network layer. We present ContentFlow, an Information-Centric network architecture which supports content routing by mapping the content name to an IP flow, and thus enables the use of OpenFlow switches to achieve content routing over a legacy IP architecture. ContentFlow is viewed as an evolutionary step between the current IP networking architecture, and a full fledged ICN architecture. It supports content management, content caching and content routing at the network layer, while using a legacy OpenFlow infrastructure and a modified controller. In particular, ContentFlow is transparent from the point of view of the client and the server, and can be inserted in between with no modification at either end. We have implemented ContentFlow and describe our implementation choices as well as the overall architecture specification. We evaluate the performance of ContentFlow in our testbed.