GCube Infrastructure Enabling Services
The gCube Infrastructure Enabling Services collectively form the lower layer of the gCube framework whose role is to glue together and support the overall operation and management of the rest of constituents of a gCube based e-Infrastructure. The facilities needed to support such kind of e-Infrastructure fall in one of the following classes: resources publishing and discovery, resources controlled sharing support, resources deployment and orchestration, resources selection support and resource workflows definition and operation. Such facilities lead to the identification and organisation of a series of services, software libraries and related technologies described in the following overall architecture.
Overall Architecture
The overall architecture of the gCube Infrastructure Enabling Services consists of three cooperating subsystems whose role, functions and relations are the following:
- The Information System represents the “core” of the overall infrastructure playing the role of a Registry in a gCube based Infrastructure. Because of its role, all resources partaking to a gCube based infrastructure are expected to interact with it (i) to inform the rest of the resources about its presence and its distinguishing features; and (ii) to discover the resources they are interested to interact with in order to accomplish its functionality. To facilitate such an interaction and to decouple the producer and consumer service logic from the internal organisation of such a subsystem two main components are envisaged, i.e. the IS-Publisher and the IS-Client supporting respectively the production/publishing and consumption/discovery phases in the interaction with a registry. This decoupling is fundamental since (i) the high work load this component is potentially subject; (ii) the robustness and fault-resiliency expected by such a critical component; and (iii) the system feature of dynamically deploying new service instances dynamically, will lead to changes in the services implementing the internals of such subsystem. This way such dynamicity is completely transparent to the Information System clients.
- The Virtual Organisation Management represents the subsystem securing the sharing and reuse of the constituents a gCube based Infrastructure, i.e. all the managed resources. The subsystem implements a security framework realising the Virtual Organisation model on which the D4Science Policy domain is based. The main functions this subsystem is called upon are related to authentication and authorisation. Because of this central role, some of the components of this subsystem are expected to be ubiquitous in a gCube-based infrastructure as to facilitate the exploitation of these features.
- The VRE Management represents the subsystem implementing the Virtual Research Environment concept. In particular, this subsystem supports the definition and deployment of such environments by exploiting the resources of a gCube based Infrastructure. Thus it needs to interact with the Information System to be acquainted of the resources that are available as well as of their status to select them appropriately and monitor the VRE operation. Moreover, it is requested to interact with the Virtual Organisation Management to both act securely and create the security context supporting each Virtual Research Environment. It will also interact with the Resource Broker during the deployment phase as to select the optimal pool of resources to exploit to deliver a VRE. From an architectural point of view it is characterised by (i) services implementing the front-end (VRE Modeler) mediating between the users' high level requirements and the subsystem back-end; (ii) services coordinating the deployment and operation of the VRE (Resource Manager); and Services supporting the dynamic deployment (Deployer, Software Repository and gHN Manager).
