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Don Quijote. Data Management for the ATLAS Automatic Production System. Miguel Branco – CERN ATC miguel.branco@cern.ch. Overview. Don Quijote New Focus Functionalities POOL Architecture Current Status NorduGrid US Grid 3(+) LCG-2 Integration with ATLAS prodsys Future plans.
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Don Quijote Data Management for the ATLAS Automatic Production System Miguel Branco – CERN ATC miguel.branco@cern.ch
Overview • Don Quijote • New Focus • Functionalities • POOL • Architecture • Current Status • NorduGrid • US Grid 3(+) • LCG-2 • Integration with ATLAS prodsys • Future plans Don Quijote - Status & Plans
Don Quijote • Data Management for the ATLAS Automatic Production System • Allow transparent registration and movement of replicas between all grid “flavors” used by ATLAS • US Grid • Nordugrid • LCG • (support for legacy systems might be introduced soon) • Avoid creating yet another catalog • which grid middleware wouldn't recognize (e.g Resource Brokers) • use existing catalogs and data management tools • find common features between tools and catalogs • bridge them and provide a unified interface • Accessible as a service • lightweight clients Don Quijote - Status & Plans
Don Quijote – new focus • Provide a single tool to end-users to manage data files • Integrates all tools that users would have to know about into a single one. E.g.: • FCpublish, FCregister, … (POOL File Catalogs) • edg-rm, edg-rmc, edg-lrc, … (EDG) • globus-rls-cli, globus-url-copy, … (Globus) • ldapsearch, … (querying information system) • rfdir, rfcp, … (common use of Castor) • Acts as a POOL-aware Replica Manager • Eases security requirements for end-users • Temporarily! Don Quijote - Status & Plans
Functionalities • search | fullSearch | searchHosts ( lpn ) • add[Restricted] ( lpn, url [, guid, fsize, md5sum ] ) • addTemporary[Restricted] ( lpn, url, nrhours [, guid, fsize, md5sum ] ) • keepUntil ( url, nrhours ) • makePermanent ( url ) • removeReplica ( url ) • remove ( lpn ) • rename ( old lpn, new lpn ) • stageOut( url ) • getToDestination ( src SE, lpn , dest ) • putToSE ( src turl, lpn, dest SE [, guid, md5sum] ) Replica Catalogs Manipulation File Movement LPN = Logical Collection Name + Logical File Name (unique) Don Quijote - Status & Plans
Functionalities - POOL • Integrates file movement with POOL XML File Catalogs • Uses DQ + POOL FC command line tools • Python scripts • Use-cases: • Get local copy of file and generate or update corresponding PoolFileCatalog.xml • (to provide input data and input POOL XML catalog for a job) • Copy and register a local copy of a file to a grid flavor given UUID in the local PoolFileCatalog.xml • (to register output data from a job) Don Quijote - Status & Plans
Architecture • Python Client • C++ client library • Configuration file indicating endpoint of each server • Servers • Per grid-flavor • GSI and insecure • Configuration file User interface tool written in Python Servers and client library written in C++ Don Quijote - Status & Plans
Changes on Server-side • Why was server-side code rewritten? • Partly because of CMS experience • Persistent connections were necessary • Connection pooling mechanism • Each request could not instantiate a connection to the grid catalog – too slow! • Partly from our initial experience • Flexible security mechanism • Either provide a single certificate for all, or delegate credentials • Initial version: • A command line tool for each grid flavor with the same syntax and same “output” • Clarens server was forking out a process that executed the request by calling the command line tool • This proved to be inefficient and too restrictive – e.g. could not maintain persistent connections across multiple requests! • Therefore, • Server code was built by extending the command line tools – each tool is now a daemon Don Quijote - Status & Plans
Current Status • Current structure: DqCore DqPoolRls DqGlobusRls DqLcgReplicaAccess DqClassicReplicaAccess C++ Client Module DqLcgInfoService DqVdtInfoService dms.py Python Module C++Python wrapper (user interface) DqNgInfoService DqLcgPoolFileCatalog DqFakePoolFileCatalog DqFactory DqConfigFile DqInterface DqMonitor DqUI DqServerLcg, DqServerNg, DqServerVdt Don Quijote - Status & Plans
NorduGrid • Globus RLS 2.x • Only Classic Storage Elements (GridFTP servers) • Information System • Connects to LDAP • Special attributes in the RLS DqCore DqGlobusRls DqClassicReplicaAccess DqNgInfoService DqFakePoolFileCatalog DqFactory DqConfigFile DqInterface DqMonitor DqUI DqServerNg Don Quijote - Status & Plans
LCG-2 • EDG/LCG RLS (v2.2) • GFAL support: • SRM/Castor support • SRM/dCache support • Classic Storage Element support • Information System: • LDAP-based (MDS) • Native POOL Support • Using POOL-1.6.5 DqCore DqPoolRls DqLcgReplicaAccess DqLcgInfoService DqLcgPoolFileCatalog DqFactory DqConfigFile DqInterface DqMonitor DqUI DqServerLcg Don Quijote - Status & Plans
US Grid 3(+) • Globus RLS 2.x • DQ supports at the moment only Classic Storage Elements (GridFTP servers) • No “information system” interface • DQ creates a “dummy” information system which consists of a local configuration file DqCore DqGlobusRls DqClassicReplicaAccess DqVdtInfoService DqFakePoolFileCatalog DqFactory DqConfigFile DqInterface DqMonitor DqUI DqServerVdt Don Quijote - Status & Plans
Integration with ATLAS prodsys • Executors are using their “native” grid tools to do file registration • But are adding extra-metadata attributes required by DQ • This allows integration with DQ • Windmill is using DQ • To locate replicas of files • Renaming of logical files to their final names (after validation) • This week: move files across grids so that each executor finds at least a replica of all files required by the jobs Don Quijote - Status & Plans
Future plans • Better integration with POOL • Must come from end-users experience • Better end-user documentation and support • For now, focus has been only on the Automatic Production System • Get “best” replica (not high priority) • within a grid • between grids • Monitoring • Still being discussed… • Reliable transfer service • Using MySQL database to manage transfers and automatic retries Don Quijote - Status & Plans
Future plans • Release command line tools appropriate for end-users • Request has been made to provide such tools for the Combined Test Beam effort • Provide servers as Pacman-caches • Much to improve • Reliability • Easy installation of client tool for users outside “grid” • Get local copies of files to non-grid machine • ? wrap in Pacman the minimal Globus GridFTP libraries • As true interoperability comes, Don Quijote goes… • Common information schema & similar catalogs • Common interface to storage resource “managers” Don Quijote - Status & Plans