Using Semantic Web Technologies to Query and Manage Information within Federated Cyber-Infrastructures

Alexander Willner, Mary Giatili, Paola Grosso, Chrysa Papagianni, Mohamed Morsey, Ilya Baldin
2017 Data  
A standardized descriptive ontology supports efficient querying and manipulation of data from heterogeneous sources across boundaries of distributed infrastructures, particularly in federated environments. In this article, we present the Open-Multinet (OMN) set of ontologies, which were designed specifically for this purpose as well as to support management of life-cycles of infrastructure resources. We present their initial application in Future Internet testbeds, their use for representing
more » ... requesting available resources, and our experimental performance evaluation of the ontologies in terms of querying and translation times. Our results highlight the value and applicability of Semantic Web technologies in managing resources of federated cyber-infrastructures. Data 2017, 2, 21 2 of 26 Modeling cloud infrastructures in a manner that supports effective matching of users' requests with available resources is a challenging task. The issue becomes even more complex in the context of distributed cloud systems with multiple infrastructure owners. In the academic research the same problem is encountered when trying to describe computational resources, scientific instruments and testbeds, which belong to different institutions and must be used by inter-disciplinary and inter-institutional collaborative teams. In such environments each infrastructure owner may model resources using their particular information and data modeling approach to set up the system quickly and attract users. The end-result, however, is user lock-in and inability to easily leverage available resources if they belong to different owners. Thus, resource matching and recommendation based on common models becomes of great importance. This paper describes Open-Multinet (OMN) [2], a set of ontologies that rely on Semantic Web (Semantic Web) [3] technologies. It was designed by an international team of academic researchers who are intimately familiar with the related problems. The OMN researchers are also involved in multiple efforts to design a federation of Future Internet and cloud testbeds spanning the US and the EU, to be used for at-scale experimentation with novel concepts in networking and distributed systems. While we briefly introduced the ontology set in [2] and presented a preliminary description of its application in the context of a federated cloud environments in [4] , in this paper we complement our previous work by an extended description of the OMN ontology set and we further added new evaluation results of the overall OMN framework. Motivation for our work comes largely from our experience with the growth of academic networking, including the proliferation of cloud testbeds. Their ad hoc attempts to federate with each other, i.e., to make their resources available to wider communities of users through common interfaces, suffer from a lack of common models to describe available resources. Testbed owners use such models chiefly to provide their users with information about available resources, e.g., compute nodes, storage, network switches, and wireless access points. Each user, in turn, employs similar models to request resources from the testbeds, describing in some detail the exact configuration of available resources needed from the testbed. Most testbeds are small when they first launch. Their designers often spend little time thinking through the information model that they wish to use to present resource information to users. Testbeds frequently rely on home-brewed solutions utilizing syntactic schema specifications serialized using XML or JSON, sometimes referred to as RSpecs, although RSpec is also a name of a specific XML dialect used by a subset of testbeds in the US. Documents expressed in those languages are passed between the users and the testbed management software in order to describe the available resources and to request specific configurations of resources for the experiments. While the built-in mechanisms in those languages allow for straightforward verification of document syntax, few mechanisms are available for validation of semantic correctness. These solutions typically rely on structure-implied semantics to validate correctness by associating semantic meaning rigidly with the position of information elements within the document. These approaches tend to work in early phases of the design. As the diversity of resources grows, however, and as the sophistication of users increases, the need arises for extension mechanisms. Demand emerges for more powerful resource descriptions. The extension mechanisms then inevitably relax the structure-implied semantics, thus making validation of documents progressively more difficult. We observed this development first-hand in the case of US Global Environment for Network Innovations (GENI) [5] and EU Future Internet Research and Experimentation (FIRE) [6] testbed-federation efforts. XML schema extensions were introduced to allow different federation members to describe the unique attributes of their cloud testbeds. The extensions, we found, made it possible to create syntactically valid but semantically invalid documents requesting resources from a testbed, e.g., by requesting that a particular operating-system image be attached to a network interface instead of to a compute node.
doi:10.3390/data2030021 fatcat:5n7kdr2j6jhu7kb4j26r6r5hs4