The GEMBus Architecture and Core Components Diego Lopez, RedIRIS

Connected in Heterogeneity GEMBus is a middleware layer to support service integration according to SOA principles in a multi-domain environment Inspired on the ESB paradigm Free application services from common concerns Security, discovery, message management, ... Go beyond the single central authority in current ESB systems Taking a step further into federated infrastructures Independent management Metadata as backbone

The Three Principles Build a flexible infrastructure able to accommodate existing service frameworks Loosely-coupled “bus of buses” Impose the fewest additional requirements on services Basic mediation services to ease integration Set the ground for simplifying lifecycle and interactions Supporting service management frameworks

Bus of Buses Based on a registry with a semantically rich internal format Service ontology Suitable for different frameworks and design styles

Minimum Requirements Limit requirements to basic aspects Message routing and traceability Security token exchange protocols Service containers and descriptions Leave the rest as an E2E issue GEMBus provides basic mediation services Security (Authentication and authorization) Accounting (Log creation and access) Composition (Orchestration and workflow) Other constraints/services/interfaces/… as an added value Part of the “common bus” or even specialized buses

Foundation for a Service Framework Middleware to support (and combine) service provisioning/integration frameworks NGN Open Service Environment TMForum/IPSphere SDF OGSA

GEMBus Elements GEMBus core infrastructure Supports service operation and provisioning Specific software elements Profiles on supporting service frameworks Specific component services Component services. Comply with an interface (service containers) Either atomic or composite Deployed at any participating service framework Can be dynamically provisioned from service repositories

The GEMBus Core The GEMBus Registry GMI: GEMBus Message Infrastructure GEMSTS: GEMBus Security Token Service GLOS: GEMBus Logging Service Service Composition Services

The GEMBus Registry Service ontology based on OWL/RDF Several service description formats WSDL, WADL, OSGi,... Service metadata Semantics come into play Complex queries and reasoning Richer import/export mechanisms Multiple instances Synchronization via publish/subscribe mechanisms Collaboration with the USDL initiative

GMI: GEMBus Messaging Infrastructure Elements built by tailored standard implementations Message processor Aspect based interceptors and event handlers Message routing module A Configuration Manager providing dynamical configuration of GMI specific components Conventions that define names and identifiers for the GEMBus endpoints, entities, elements, attributes and properties

GEMSTS: GEMBus Security Token Service User authentication outside the GEMBus scope STS split into two atomic services TTS: AuthN (token issuance) AS: AuthR (token validation) Both can use external sources for Identity: Attribute authorities Policies: PDPs Session tokens to reduce authorization overhead

GLOS: GEMBus Logging Service A key facility for accounting, statistics, diagnostics,… Handler integrated in the GMI GLOS service instance at each participating framework Common log repository/ies Collection of interactions at the GMI level RDF as internal format

Service Composition Services Orchestration implemented by a WS-BPEL execution engine Apache ODE is the current choice Implementation and management environment Eclipse plugin based on BPMN Workflow integration into service deployment Taverna tools Awaiting for OSGi interface availability

Service Integration Patterns Identified and exercised through actual integration of current GÉANT services

Core Access Patterns: Full Integration Adapting elements relieve services from direct interaction with the core Deployed at the bus level or in service containers

Core Access Patterns: Mixed Integration Fine-grained control of core behavior through direct API calls Opens core usage to services deployed outside GEMBus boundaries

GEMBus So Far Architecture defined and validated Prototypes of (most) core elements Registry STS Composition Being discussed and evaluated by potential user communities Soon to be integrated in an openly available portal Demonstrator on GEMBus concepts and applicability Implementation of an AC (Autonomous Computing) application Come and see the demo!

The Task Ahead: Consolidating GEMBus Making the core elements achieve a stable status Service characterization What makes a service suitable for being deployed in GEMBus What makes it suitable for using the GEMBus Core What is required to be included in the GEMBus Registry What is required to be composed with other services Service deployment mechanisms Service repositories Service containers Validation, deployment and provisioning mechanisms Documentation Collecting experience in a GEMBus Cookbook

The Middleware Mantra