András Kövi

An Eclipse-Based Framework for AIS Service Configurations

In the paper, we propose an Eclipse-based model-driven framework to support an integrated development, analysis and deployment of Application Interface Specification (AIS) service configurations. Service configurations are first captured by platform-independent models (PIM), which directly correspond to the AIS standard itself, and abstract from vendor-specific details. Specificities of vendor-specific AIS middleware are incorporated into platform-specific models (PSM), which are derived from PIMs by automatic model transformations. Model analysis can be carried out either on the PIM-level to ensure standard compliance of a given service configuration, or on the PSM-level to detect availability bottlenecks by formal analysis early in the service configuration design. Finally, deployment descriptors of the selected AIS platform are generated from verified service configurations by automatic code generation techniques.

Applying MDA approach for the SA forum platform

The Application Interface Specification of the Service Availability Forum is a set of relatively new but well elaborated service specifications that facilitate the creation of highly available, fault tolerant applications. Even if not many, but there exist applications developed based on the specifications; however, a systematic way for creating those has not been published yet. This work describes a model-driven framework for the development of AIS based applications. It enables the creation and manipulation of the application models that are used for the generation of system configuration and component code skeletons, and which can be used for the automatic checking of correctness and various other non-functional requirements.

Analytics of resource transients in cloud-based applications

Guaranteeing QoS of services deployed in clouds is a key issue in cloud environments. Cloud services rely heavily on sharing resources between tenants; users have only partial knowledge and control of them. Limited observability and controllability make guaranteeing QoS a challenging task. Many important classic approaches to QoS assurance cannot be adopted, as for a tenant resource arbitration is a black box. Unexpected changes in resource allowance and characteristics introduce novel risks for demanding applications, most importantly soft real-time ones. We introduce the concept of applicationintegrated early warning sensors – ‘mystery shoppers’ – to increase the observability of the platform performability state. Mystery shoppers are special, continuously running benchmarks that run as low footprint applications. They deliver fine-grained reports by simulating application resource usage and measuring platform characteristics. This enables inferring the hidden resource sharing characteristics of public clouds. The derived metrics can aid deployment planning and control application-level fault tolerance mechanisms.

Robustness Testing of Standard Specifications-Based HA Middleware

Using middleware implementations, instead of integrating the fault tolerance in the applications themselves, for providing stateful services highly availably has become the best practice in many industries including the telecommunication, computing and other areas. Robustness of these implementations toward user failures is essential for the overall availability of the systems. This paper summarizes the methodology for executing robustness tests on Service Availability Forum Application Interface Specification based middleware and describes the results of the conducted experiments with the Open SAF open source middleware implementation. Finally, the results of the measurements/experiments are analyzed using the AMBERRAW Data Repository.

Making legacy services highly available with OpenAIS: an experience report

We report our experiences on application development with the open source OpenAIS framework, which is an implementation of the standard Application Interface Specification (AIS) issued by the Service Availability Forum. Our focus is put on integrating existing (legacy) applications or services into the AIS framework (where the source code of these services is not available) in order to make such services highly available. This is achieved by using Proxy components, which are responsible for managing the High Availability (HA) lifecycle of legacy services (called proxied components). We estimate the availability of legacy services as provided by using redundant proxy and proxied components in the OpenAIS framework on a benchmark service architecture. Furthermore, as the AIS standard does not contain any recommendation on business-related communication, in the paper, we propose to use communication mediation to forward requests to service provider components and responses back to the service consumers.

A methodology for standards-driven metamodel fusion

This paper describes a model-driven development methodology that supports the design, implementation and maintenance of complex, evolving systems. The key asset in this methodology is a domain specific design ontology which incorporates multiple aspects of the system under design. The methodology considers different input data and metamodels during the information fusion and uniformization. The aim of this ontology building is threefold: i) it helps the early phase of system design and modeling, ii) it provides a basis for conformance check and validation, and iii) facilitates the generation of skeletons (data mode, service interface, process structure, business rules and assertions, etc.) which are conform with the standards and domain requirements. The methodology is illustrated on an example logistics system of the e-Freight European project.