NOVA Networked Object-based EnVironment for Analysis P. Nevski, A. Vaniachine, T. Wenaus NOVA is a project to develop distributed object oriented physics analysis components, adaptable to different experiments. A job configuration manager uses a scripting interface to provide web-based editing, submission and cataloguing of analysis jobs, both user-level and experiment-wide, centrally managed in a database. A client/server system distributed over compute nodes provides job submission and monitoring across facilities, which may span several sites. A file catalog records production relationship of data files generated by an experiment. NOVA provides database tools for geometry and parameter object storage. A NOVA web-based browser navigates a relational database storing hierarchically structured dataObjects. Clients may access database information from the code or through a CORBA-specified interface. NOVA components have been tested and deployed in the STAR and ATLAS environments. February 7, 2000

CHEP in Padova Outline Goals Requirements Architecture Components Details Summary

February 7, 2000CHEP in Padova Motivations Unprecedented data volume and software complexity in new large High Energy and Nuclear Physics experiments at RHIC (BNL) and LHC (CERN)  New approaches to analysis and data handling software  Distributed computing environment (DCE) is vital and increasingly powerful  Experience in developing DCE solutions for STAR  Build on experience to develop DCE tools for use in similarly challenging environments

February 7, 2000CHEP in Padova Goals Develop software tools for –coordination and control of widely distributed analysis development and physics analysis activity –distributed management and analysis of very large datasets –enhanced robustness, reusability and maintainability of analysis software For application in many global computing environments (ATLAS, STAR, …) –generic tools not tied to specific implementation choices –select, templatable implementations provided such that NOVA components can be used in a baseline framework

February 7, 2000CHEP in Padova Requirements Support wide area data intensive analysis Define middleware services are required to permit analysis applications to effectively run over wide area networks Provide a rich set of features that applications can select and use to obtain the level of service they need to operate Define the features and the API's necessary to allow the application and middleware to communicate Integrate the middleware API's with the applications

February 7, 2000CHEP in Padova Design Approach Small, modular components; application-neutral interfaces –Can be used as a coherent framework or in isolation to extend existing analysis systems Focused on support for C++ based analysis –Used for all RHIC, LHC, other large experiments Emphasis on user participation in iterative development; real-world prototyping and testing (STAR, ATLAS) Extensive use of existing tools and technologies –Must be readily available, true or de facto standards, well supported, widely used or showing good growth

February 7, 2000CHEP in Padova Component-based Architecture

February 7, 2000CHEP in Padova Tools and Technologies Third party tools and technologies used in NOVA: –MySQL: relational database for catalogs, state information and simple objects: C-structs –Perl: Unix scripting and web development tool –Apache: customizable (Perl & PHP) web server for communication and monitoring –CORBA: low-volume interprocess data exchange –ROOT: visualization and analysis tools

February 7, 2000CHEP in Padova Components NOVA components fall into four domains –Regional Center Central management and execution of analysis –Remote Client Mobile Analysis –Middleware Components Data exchange and navigation tools Client/Server object request brokerage –Data Management Data repository, catalogue, and interface Data model for simple objects (C-structs)

February 7, 2000CHEP in Padova Dynamic Binding Problem: –A user has a new idea that was not foreseen at the beginning. User modifies the structure of one object in his application. Application stores new objects in the database. –Remote applications unaware of a new functionality may request objects in old format. Solution: –Application: provides metadata request (name, time, selectors...) and the application dataObject dictionary –Database server: provides dataObject and the dictionary –Object Request Broker module: converts dataObject according to the application dictionary

February 7, 2000CHEP in Padova Dynamic Object Broker Central Database Server Middleware Services Remote Application Clients Application DataObject Database DataObject Database Dictionary Application Dictionary Parameters Repository Object Request Broker

February 7, 2000CHEP in Padova Forward Compatibility Benefits: –Separation of database and analysis applications –Robust interface (via built-in type checking) –Dictionary built from C-header files or IDL-files –Database access is independent of application code version: user can read new dataObjects with an old executable Usage: –Parameters data management (versioned geometry and reconstruction constants support)

February 7, 2000CHEP in Padova Static Binding Problem: –Remote application (web browser) navigates current database hierarchy. Solution: –Object Request Broker at the Regional Center serves dynamic HTML dataObjects in format tailored according to application ID: Netscape or MS Internet Explorer

February 7, 2000CHEP in Padova Remote Application Client Static Object Broker NOVA Browser Regional Center Database Server Middleware Services Database API Module Application DataObject Database DataObject Database API Call Application ID Parameters Repository Apache Web Server

February 7, 2000CHEP in Padova Layered Interface

February 7, 2000CHEP in Padova Data Model

February 7, 2000CHEP in Padova Job monitoring system Cataloguing Analysis Workflow fileCatalog Job configuration manager

February 7, 2000CHEP in Padova Grand Challenge Interface database GC System StIOMaker fileCatalog tagDB Query Monitor Cache Manager Query Estimator gcaClient FileCatalog IndexFeeder GCA InterfaceSTAR Components Index Builder

February 7, 2000CHEP in Padova Limiting Dependencies Experiment-specific IndexFeeder server –IndexFeeder read the “tag database” so that GCA “index builder” can create index FileCatalog server –FileCatalog queries the “file catalog” database of the experiment to translate fileID to HPSS & disk path & GCA-dependent gcaClient interface –Experiment sends queries and get back filenames through the gcaClient library calls

February 7, 2000CHEP in Padova Summary What is NOVA? Framework components for distributed computing What are NOVA components? Configuration manager for analysis jobs Distributed job submission and monitoring system Analysis workflow catalog Database for versioned dataObjects Brokered extraction of dataObjects Web-based database navigation tool