Introduction to Grid Computing and the Trigrid VL infrastructure Fabio Scibilia INFN – Catania 08.01.2007, Messina

Fundamentals of Grid Computing Messina, , 08.01.2007 2

The Grid and the Internet It is considered the next step in the evolution of distributed computing Adopts the Internet as communication infrastructure for exchanging information It is considered as the equivalent of the Internet in terms of exchanging of computational power Messina, , 08.01.2007 3

Computing Grid The Grid idea The user: The society: Computing power is made available over the Internet Some computing farms produce computing power to be shared The society will provide for grid facilities allowing the user to access to its grid resources and providing for proper tools One user wants to access to intensive computational power Now the user accesses to grid facilities as a grid user He/she comes to an agreement with some society that offers grid services The user: Does not need to know what stays beyond the user interface Can access to a massive amounts of computational power through a simple terminal The society: Can extend grid facilities at any moment Manages the architecture of the grid Defines policies and rules for accessing to grid resources Messina, , 08.01.2007 4

Why Computing Grids now? Because the amount of computational power needed by many applications is getting very huge Because the amount of data requires massive and complex distributed storage systems To make easier the cooperation of people and resources belonging to different organizations To access to particular instrumentation that is not easily reachable in a different way Because it is the next step in the evolution of distribution of computation Thousands of CPUs working at the same time on the same task From hundreds of Gigabytes to Petabytes (1015) produced by the same application. People of several organizations working together to achieve a common goal Because it cannot be moved or replicated or its cost is too much expensive. To create a marketplace of computational power and storage over the Internet Messina, , 08.01.2007 5

Who is interested in Grids? Research community, to carry out important results from experiments that involve many and many people and massive amounts of resources Enterprises that can have huge computation without the need for extending their current informatic infrastructures Businesses, which can provide for computational power and data storage against a contract or for rental Messina, , 08.01.2007 6

Virtual Organizations Virtual Organization (VO) Is a collection of people and resources working together to achieve the same goal It is cross-domain (people and resources) One user Identified by his/her personal X.509 certificate issued by trusted Certification Authorities (CA) Can belong to more than one VO at the same time Does not require detailed knowledge of grid technologies to access to the Grid VO INFN Medical Institure Messina, , 08.01.2007 7

Virtual Laboratory A new way of cooperating in experiments A platform that allow scientists to work together in the same “Virtual” Laboratory Strictly correlated to Grids and Virtual Organizations Messina, , 08.01.2007 8

Properties of Grids Transparency Openness Heterogeneity Scalability The complexity of the Grid architecture is hidden to the final user The user has to be able to use a Grid as it was a unique virtual supercomputer Resources must be accessible setting their location apart Openness Each subcomponent of the Grid is accessible independently of the other components Heterogeneity Grids are composed by several and different resources Scalability Resources can be added and removed from the Grid dynamically Fault Tolerance Grids must be able to work even if a component fails or a system crashes Concurrency Different processes on different nodes must be able to work at the same time accessing to the same resources Messina, , 08.01.2007 9

Challenged Issues in Grids (i) Security Authentication and authorization of users Confidentiality and not repudiation Information Services Discovery and monitoring of Grid resources Checking for health-status of resources To be the base for any decision making processes File Management Creation, modification and deletion of files Replication of files to improve access performances Ability to access to files without the need to move them locally to the code Administration Systems to administer Grid resource respecting local administration policies Messina, , 08.01.2007 10

Challenged Issues in Grids (ii) Resource Brokering To schedule tasks across different resources To make optimal or suboptimal decisions To reserve (in the future) resources and network bandwidth Naming services To name resources in an unambiguous way in the Grid scope Friendly User Interfaces Because most of Grid users have nothing to do with computing science (physicians, chemistries, videogame players . . .) Graphical User Interfaces (GUIs) Grid Portals (very similar to classical Web Portals) Command Line Interfaces (CLIs) for experts Messina, , 08.01.2007 11

On the Infrastructure Messina, , 08.01.2007 12

The Trigrid Infrastructure Messina, , 08.01.2007 13

Infrastruttura di TriGrid Grid site in Catania: INAF, INFN, DMI, DIIT About 100 machines dual CPU 32/64 bit with a computing power of about 300 kSpecInt2000. 30 TBs of storage EIDE-to-SCSI or FC-to-SATA in RAID 0,1,5 About 20 workstations Grid site in Messina: Facoltà di Ingegneria and CECUM About 80 machines dual CPU 32/64 bit with a computing power of about 240 kSpecInt2000. 20 TBs of storage EIDE-to-SCSI or FC-to-SATA in RAID 0,1,5 Grid site in Palermo: Dipartimento di Fisica e Tecnologie Relative (DIFTER) About 30 machines dual CPU 32/64 bit with a computing power of about 00 kSpecInt2000. 10 TBs di storage EIDE-to-SCSI or FC-to-SATA in RAID 0,1,5 Messina, , 08.01.2007 14

Integration with INFN Production Grid INFN Production Grid started in 1999 Working over the GARR (the Italian research communication network) Managed by INFN More than 20 sites, at the moment http://grid-it.cnaf.infn.it/ Messina, , 08.01.2007 15

Integration with EGEE Enabling Grids for E-science (EGEE) Funded by European Union Working over the GEANT network (the network of the European research community) 70 partners of 27 countries Was born for conducting physics applications. Now extended to other fields, such as Earth Observation (EO), Bioinformatics and so on. http://www.eu-egee.org/ EGEE is providing a production quality grid infrastructure spanning more than 30 countries with over 150 sites to a myriad of applications from various scientific domains, including Earth Sciences, High Energy Physics, Bioinformatics and Astrophysics." Bob Jones (Project Director) Messina, , 08.01.2007 16

Application Areas (1/2) Physicical Science Applications GryPhiN, http://www.gryphin.org/ Particle Physics DataGrid (PPDG), http://grid.fnal.gov/ppdg/ GridPP, http://www.gridpp.ac.uk/ AstroGrid, http://www.astrogrid.org/ Life Science Applications Protein Data Bank (PDB), http://www.rcsb.org/pdb/Welcome.do Biomedical Informatics Research Network (BIRN), http://www.nbirn.net/ Telemicroscopy, http://ncmir.ucsd.edu/ myGrid, http://www.mygrid.org.uk/ Messina, , 08.01.2007 17

Application Areas (2/2) Engineering Oriented Applications NASA Information Power Grid (IPG), http://www.ipg.nasa.gov/ Grid Enabled Optimization and Design Search for Engineering (GEODISE), http://www.geodise.org/ Commercial Applications Butterfly Grid, http://www.butterfly.net/ Everquest, http://www.everquest.com/ E-Utility ClimatePrediction experiment, http://www.climateprediction.net/ Messina, , 08.01.2007 18

The Architecture and the Middleware Messina, , 08.01.2007 19

The Globus Alliance Globus Alliance The Globus Toolkit (GT) It is a community of people of different organizations involved in the design and development of Grid Technologies Università dell’Illinois, Argonne National Laboratory, University of Edinburgh, EPCC, etc… The Globus Toolkit (GT) It is a standard di fatto Is is a set of services Fourth release, at the moment Involves Web Services Interfaces http://www.globus.org/ The Global Grid Forum (GGF) It is a forum for Grid researchers Its goal is to define standards and protocols for Grids It is organized in Work Groups (WGs) http://www.ggf.org Messina, , 08.01.2007 20

The Globus hourglass model The hourglass model Reference model used by Globus designers Levels of services Local Operating Systems: Management of several types of resources, local scheduling systems, monitoring and so on. Core Globus Services: Services to create and manage the Grid infrastructure Diverse Global Services: Grid based applications Messina, , 08.01.2007 21

Layers Fabric Connectivity Resource Collective Application Manages resources Connectivity Security Context (authentication, authorization) Single Sign On (SSO) Resource Allocation, reservation and monitoring of resources Data movement Collection of information on resources Collective Discovery of resources Data cataloguing and replication Workflow management Application User applications Tools and interfaces Application Collective Resource Connectivity Fabric Messina, , 08.01.2007 22

Globus Services Messina, , 08.01.2007 23

Architecture Overview Messina, , 08.01.2007 24

The Single Sign On (SSO) It is a way to sign in to the Grid just one time and access to all services you need It is done via proper command lines of the User Interface and providing a valid certiicate A user submits his certificate to the VOMS server VO Membership Service (VOMS) Issues proxies to users with VOMS extensions Assigns groups/roles/capabilities to the users Verifies user credentials (ceritificate) Messina, , 08.01.2007 25

Computing Element (CE) Local Resource Manager (LRMS) It is NOT a Grid component Local administration Dispatches job across Worker Nodes according to local policies Accessed by local users Computing Element Service oriented Exports computing power of the LRMS to grid users Maps grid users to local users Wraps a “grid job” into a “local job” Gatekeeper Access point of the CE Manages one or more job queues Transparent interface to the LRMS Worker Nodes More than one (farm) To execute grid jobs, a specific environment must be set Messina, , 08.01.2007 26

Storage Element (SE) Mass Storage System (MSS) It is NOT a grid component Manages the local storage device Hard disks, digital tapes Storage Resource Manager (SRM) Is the grid compliant interface to access to the storage system Maps grid users to local users Access and control to the MSS Grid FTP compliant daemons Grid compliant daemons for uploading/downloading of grid files On top of the local MSS Protocols: gsiftp, rfio, dcap Grid client Any user/process with a valid proxy Messina, , 08.01.2007 27

Data Management LHC File Catalogue (LFC) Logical File Name (LFN) Hierarchical file catalogue Each VO has its own catalogue Logical File Name (LFN) The name of a file within the LFC To each LFN correspond one or more replicas stored on different SEs lfn://grid/cometa/file.txt Storage URL (SURL) The name of a replica within a SE To each SURL correspond more TURLs srm://se1.cometa.it/some/path/file.txt Transport URL (TURL) Is the name of the physical file plus the grid FTP protocol to access to it gsiftp://se1_disk2.cometa.it/local/path/file1.txt Messina, , 08.01.2007 28

Information System Globus Meta Directory Server (MDS) Hierarchical, based on LDAP servers The user can query the system at every level The higher the information is in the tree, the older it is Grid Resource Information Service (GRIS) Collects info on that resource Static or dynamic info Uses sensors Grid Index Information Service (GIIS) One for each site Collects info from above GRISes Caches info according to its validity time Queries above GRISes or GIISes whether needed Berkeley Database Information Index (BDII) Same behaviour but more stable Messina, , 08.01.2007 29

Workload Management System (1/4) The grid user describes a job via a Job Description Language (JDL) document. Some input files (Input Sandbox) can be attached to the JDL doc. The grid user submits the JDL job using the command line interface and waits for reply. The Resource Broker gets and stores the JDL document together with attached input files. The just generated jobId is sent back to the user to refer to that job univocally in the future Messina, , 08.01.2007 30

Workload Management System (2/4) The Resources Broker executes a special algorithm (matchmaking) and chooses a Computing Element according to best-fit rules The job is handed to the chosen CE together with the Input SandBox The Computing Element accepts the job and queues it. The job starts execution over the Local Resources Management System (LRMS) Messina, , 08.01.2007 31

Workload Management System (3/4) When the job terminates, the produced output is sent back to the Resource Broker The Resource Broker gets the results and the Output Sandbox and stores them in the local repository At the same time, the Computing Element notifies the Logging & Bookkeeping Now the job output is available on the Resource Broker Messina, , 08.01.2007 32

Workload Management System (4/4) The User queries the Logging and Bookkeping to have a look on his/her jobs and realizes that the job has terminated. The User downloads the Output Sandbox from the Resource Broker. The Resource Broker clears all no more needed info from its repository to save space. The job life cycle has terminated !!! Messina, , 08.01.2007 33

References TriGrid Homepage Consorzio COMETA Homepage http://www.trigrid.it Consorzio COMETA Homepage http://www.consorzio-cometa.it INFN Production Grid http://grid-it.cnaf.infn.it/ EGEE http://www.eu-egee.org/ Messina, , 08.01.2007 34