1. INFSO-RI-508833 Enabling Grids for E-sciencE www.eu-egee.org Information System Giuseppe La Rocca Valeria Ardizzone INFN Catania 4th EGEE Conference Pisa 23.October.2005

2. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 2 Outline This presentation covers the following arguments:  Introduction to lcg-infosites and lcg-info  Introduction to R-GMA  Grid Monitoring Architecture (GMA).  R-GMA in depth: - Registry,Schema, Producer and Consumer - Query Type - R-GMA Browser  Security in R-GMA  Introduction to DGAS

3. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 3 (lcg-infosites, R-GMA, DGAS) Information & Accounting Systems

4. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 4 lcg-infosites (the present) lcg-infosites (the present)

5. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 5 How to discover resources ? Once an user is logged into an User Interface (s)he is ready to take advantage of the Grid Power for his/her own application. But what are the available resources to accomplish his/her tasks? The answer to this question comes through the interactions with the Information System (IS). The Information System (IS) provides information about the LCG-2 Grid resources and their status.

6. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 How to discover resources (cont) The data published in the IS conforms to the GLUE (Grid Laboratory for a Uniform Environment) Schema. The GLUE Schema aims to define a common conceptual data model to be used for Grid resources. In LCG-2, the BDII (Berkeley DB Information Index), based on the Monitoring and Discovery Service (MDS), was adopted as main provider of the Information Service. In gLite Relational Grid Monitoring Architecture will be adopted as IS.

7. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 Monitoring and Discovery Service Computing and storage resources at a site implement an entity called Information Provider, which generates the relevant information of the resource (e.g.: the used space in a SE). This information is published via an LDAP server by the Grid Resource Information Servers, or GRISes.

8. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 In each site an element called the Site Grid Index Information Server (GIIS) collects all the information of the different GRISes and publishes it. This BDII queries the GIISes and acts as a cache, storing information about the Grid status in its database. Monitoring and Discovery Service

9. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 Querying the BDII a user or a service has all the available information about the status of the grid resources. Moreover in order to get more up-to-date information it is possible to querying directly the GIISes or GRISes. Monitoring and Discovery Service

10. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 How to query the IS? In order to query directly the IS elements two higher level tools are provided. lcg-infositeslcg-info These tools should be enough for most common user needs and will usually avoid the necessary of raw LDAP queries.

11. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 lcg-infosites The lcg-infosites command can be used as an easy way to retrieve information on Grid resources for the most use cases. USAGE: lcg-infosites --vo options -v --is

12. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 lcg-infosites options

13. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 13 Obtaining information about CE $ lcg-infosites --vo gilda ce **************************************************************** These are the related data for gilda: (in terms of queues and CPUs) **************************************************************** #CPU Free Total Jobs Running Waiting ComputingElement ------------------------------------------------------------------------------------------ 4 3 0 0 0 cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-long 4 3 0 0 0 cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-short 34 33 0 0 0 grid010.ct.infn.it:2119/jobmanager-lcgpbs-long 16 16 0 0 0 grid011f.cnaf.infn.it:2119/jobmanager-lcgpbs-long 1 1 0 0 0 grid006.cecalc.ula.ve:2119/jobmanager-lcgpbs-log 2 1 1 0 1 gildace.oact.inaf.it:2119/jobmanager-lcgpbs-short [..] $ lcg-infosites --vo gilda ce --v 2 RAMMemory Operating System System Version Processor CE Name --------------------------------------------------------------------------------------------------------------------------------- 1024 SLC 3 P4 ced-ce0.datagrid.cnr.it 4096 SLC 3 Xeon cn01.be.itu.edu.tr 1024 SLC 3 PIII cna02.cna.unicamp.br 917 SLC 3 PIII gilda-ce-01.pd.infn.it 1024 SLC 3 Athlon gildace.oact.inaf.it 1024 SLC 3 Xeon grid-ce.bio.dist.unige.it [..]

14. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 14 Obtaining information about SE $ lcg-infosites --vo gilda se ************************************************************** These are the related data for gilda: (in terms of SE) ************************************************************** Avail Space(Kb) Used Space(Kb) Type SEs -------------------------------------------------------------------------------------- 143547680 2472756 disk cn02.be.itu.edu.tr 168727984 118549624 disk grid009.ct.infn.it 13908644 2819288 disk grid003.cecalc.ula.ve 108741124 2442872 disk gildase.oact.inaf.it 28211488 2948292 disk testbed005.cnaf.infn.it 349001680 33028 disk gilda-se-01.pd.infn.it 31724384 2819596 disk cna03.cna.unicamp.br 387834656 629136 disk grid-se.bio.dist.unige.it

15. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 15 Listing the close Storage Elements $ lcg-infosites --vo gilda closeSE Name of the CE: cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-long Name of the close SE: cn02.be.itu.edu.tr Name of the CE: cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-short Name of the close SE: cn02.be.itu.edu.tr Name of the CE: grid010.ct.infn.it:2119/jobmanager-lcgpbs-long Name of the close SE: grid009.ct.infn.it Name of the CE: grid011f.cnaf.infn.it:2119/jobmanager-lcgpbs-long Name of the close SE: testbed005.cnaf.infn.it

16. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 16 Listing tags of installed software $ lcg-infosites --vo gilda tag ************************************************************************** Information for gilda relative to their software tags included in each CE ************************************************************************** Name of the TAG: VO-gilda-GEANT Name of the TAG: VO-gilda-GKS05 Name of the CE:cn01.be.itu.edu.tr Name of the TAG: VO-gilda-slc3_ia32_gcc323 Name of the TAG: VO-gilda-CMKIN_5_1_1 Name of the TAG: VO-gilda-GEANT Name of the TAG: VO-gilda-GKS05 Name of the CE:grid010.ct.infn.it [..]

17. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 17 lcg-info intro This command can be used to list either CEs or the SEs that satisfy a given set of conditions, and to print the values of a given set of attributes. The information is taken from the BDII specified by the LCG_GFAL_INFOSYS environment variable. The query syntax is like this: attr1 op1 valueN,... attrN opN valueN where attrN is an attribute name op is =, >= or <=, and the cuts are ANDed. The cuts are comma-separated and spaces are not allowed.

18. Enabling Grids for E-sciencE INFSO-RI-508833 USAGE lcg-info --list-ce [--bdii bdii] [--vo vo] [--sed] [--query query] [--attrs list] lcg-info --list-se [--bdii bdii] [--vo vo] [--sed] [--query query] [--attrs list] lcg-info --list-attrs lcg-info --help lcg-info usage

19. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 19 lcg-info options

20. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 20 Get the list of supported attributes $ lcg-info --list-attrs Attribute name Glue object class Glue attribute name MaxTime GlueCE GlueCEPolicyMaxWallClockTime CEStatus GlueCE GlueCEStateStatus TotalJobs GlueCE GlueCEStateTotalJobs CEVOs GlueCE GlueCEAccessControlBaseRule TotalCPUs GlueCE GlueCEInfoTotalCPUs FreeCPUs GlueCE GlueCEStateFreeCPUs CE GlueCE GlueCEUniqueID WaitingJobs GlueCE GlueCEStateWaitingJobs RunningJobs GlueCE GlueCEStateRunningJobs CloseCE GlueCESEBindGroup GlueCESEBindGroupCEUniqueID CloseSE GlueCESEBindGroup GlueCESEBindGroupSEUniqueID SEVOs GlueSA GlueSAAccessControlBaseRule UsedSpace GlueSA GlueSAStateUsedSpace AvailableSpace GlueSA GlueSAStateAvailableSpace Type GlueSE GlueSEType SE GlueSE GlueSEUniqueID Protocol GlueSEAccessProtocol GlueSEAccessProtocolType ArchType GlueSL GlueSLArchitectureType Processor GlueSubCluster GlueHostProcessorModel OS GlueSubCluster GlueHostOperatingSystemName Cluster GlueSubCluster GlueSubClusterUniqueID Tag GlueSubCluster GlueHostApplicationSoftwareRunTimeEnvironment Memory GlueSubCluster GlueHostMainMemoryRAMSize

21. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 21 lcg-info examples $ lcg-info --list-ce --query 'TotalCPUs>=30,OS=SL*' --attrs 'RunningJobs,FreeCPUs‘ - CE: grid010.ct.infn.it:2119/jobmanager-lcgpbs-long - RunningJobs 0 - FreeCPUs 33 - CE: grid010.ct.infn.it:2119/jobmanager-lcgpbs-short - RunningJobs 0 - FreeCPUs 33 - CE: grid010.ct.infn.it:2119/jobmanager-lcgpbs-infinite - RunningJobs 1 - FreeCPUs 33 - CE: skurut1.cesnet.cz:2119/jobmanager-lcgpbs-long - RunningJobs 0 - FreeCPUs 26 - CE: skurut1.cesnet.cz:2119/jobmanager-lcgpbs-gilda - RunningJobs 0 - FreeCPUs 26 [..] List all the CE(s) in the BDII satisfying given conditions

22. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 22 lcg-info examples (cont.) $ lcg-info --list-ce --query 'FreeCPUs >= 30‘--attrs ‘FreeCPUs’ - CE: grid010.ct.infn.it:2119/jobmanager-lcgpbs-long - FreeCPUs 33 - CE: grid010.ct.infn.it:2119/jobmanager-lcgpbs-short - FreeCPUs 33 - CE: grid010.ct.infn.it:2119/jobmanager-lcgpbs-infinite - FreeCPUs 33 [..] List all the CE(s) which satisfying the condition FreeCPU >=30

23. Enabling Grids for E-sciencE INFSO-RI-508833 4 th EGEE Conference - Pisa, 24-28 October 2005 23 Print all the tags published by a specific query $ lcg-info --list-ce --query 'CE=*grid010.ct.infn.it:2119*‘ --attrs ‘Tag’ PBS INFN CATANIA LCG-2 LCG-2_1_0 LCG-2_1_1 LCG-2_2_0 LCG-2_3_0 LCG-2_3_1 LCG-2_4_0 R-GMA AFS CMS-1.1.0 ATLAS-6.0.4 GATE-1.0.0-3 LHCb-1.1.1 IDL-5.4 CMSIM-125 ALICE-4.01.00 ALIEN-1.32.14 POVRAY-3.5 DEMTOOLS-1.0 CMKIN-VALID CMKIN-1.1.0 CMSIM-VALID CSOUND-4.13 MPICH VIRGO-1.0 CMS-OSCAR-2.4.5 LHCb_dbase_common-v3r1 GEANT4-6 VLC-0.7.2 EGEODE-1.0 RASTER3D SCILAB-2.6 G95-3.5.0 MAGIC-6.19 CODESA3D-1.0 VO-gilda-slc3_ia32_gcc323 VO-gilda-CMKIN_5_1_1 VO-gilda-GEANT VO-gilda-GKS05

24. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 24 List the CEs with a particular SW $ lcg-info –vo gilda --list-ce --query ‘Tag=*MPICH*’ --attrs ‘CE’ - CE: cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-long - CE cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-long - CE: cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-short - CE cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-short - CE: grid010.ct.infn.it:2119/jobmanager-lcgpbs-long - CE grid010.ct.infn.it:2119/jobmanager-lcgpbs-long - CE: grid011f.cnaf.infn.it:2119/jobmanager-lcgpbs-long - CE grid011f.cnaf.infn.it:2119/jobmanager-lcgpbs-long - CE: ced-ce0.datagrid.cnr.it:2119/jobmanager-lcgpbs-long - CE ced-ce0.datagrid.cnr.it:2119/jobmanager-lcgpbs-long [..]

25. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 25 List the SEs satisfying given query $ lcg-info –vo gilda --list-se --query ‘AvailableSpace>=100000’ --attrs ‘CloseCE’ - SE: cn02.be.itu.edu.tr - CloseCE cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-long cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-short cn01.be.itu.edu.tr:2119/jobmanager-lcglsf-infinite - SE: grid009.ct.infn.it - CloseCE grid010.ct.infn.it:2119/jobmanager-lcgpbs-long grid010.ct.infn.it:2119/jobmanager-lcgpbs-short grid010.ct.infn.it:2119/jobmanager-lcgpbs-infinite - SE: ced-se0.datagrid.cnr.it - CloseCE ced-ce0.datagrid.cnr.it:2119/jobmanager-lcgpbs-long ced-ce0.datagrid.cnr.it:2119/jobmanager-lcgpbs-short ced-ce0.datagrid.cnr.it:2119/jobmanager-lcgpbs-infinite - SE: grid003.cecablc.ula.ve - CloseCE grid006.cecalc.ula.ve:2119/jobmanager-lcgpbs-cert grid006.cecalc.ula.ve:2119/jobmanager-lcgpbs-long grid006.cecalc.ula.ve:2119/jobmanager-lcgpbs-short grid006.cecalc.ula.ve:2119/jobmanager-lcgpbs-infinite [..]

26. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 26 R-GMA (the future)

27. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 27 Introduction to R-GMA Relational Grid Monitoring Architecture (R-GMA) –Developed as part of the EuropeanDataGrid Project (EDG) –Now as part of the EGEE project. –Based the Grid Monitoring Architecture (GMA) from the Global Grid Forum (GGF). Uses a relational data model. –Data is viewed as a table. –Data structure defined by the columns. –Each entry is a row (tuple). –Queried using Structured Query Language (SQL).

28. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 28 Grid Monitoring Architecture PRODUCER CONSUMER REGISTRY Store location Lookup location Transfer Data The Producer stores its location (URL) in the Registry. The Consumer looks up producer URLs in the Registry. The Consumer contacts the Producer to get all the data or the Consumer can listen to the Producer for new data.

29. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 29 R-GMA in depth There is no central repository!!! We have only a “Virtual Database”. Schema is a list of table definitions. Registry is a list of data producers with all its details. Producers publish data. Consumer read data published. VIRTUAL DATABASE TABLE 1, Colum defs TABLE 2, Colum defs TABLE 3, Colum defs TABLE 4, Colum defs SCHEMA TABLE 1,Producer P1 details TABLE 2,Producer P1 details TABLE 2,Producer P2 details TABLE 2,Producer P3 details TABLE 3,Producer P2 details TABLE 3,Producer P1 details TABLE 3,Producer P3 details REGISTRY MEDIATOR P1 P2 P3 C1C2 SQL “CREATE TABLE” SQL “INSERT” SQL “SELECT”

30. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 30 Producer Types Primary Producer Secondary Producer On-Demand Producer User Code Producer API Producer Service Tuple Storage C Control and inserted tuples Queries Tuples User Code Producer API Producer Service Tuple Storage C Control only Queries Tuples SELECT * Tuples P User Code Producer API Producer Service C Control only Queries Tuples Queries User Code

31. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 31 Query Types Continuous Latest History Static P1 TABLE 1,Producer P1 details TABLE 2,Producer P1 details TABLE 2,Producer P2 details TABLE 2,Producer P3 details TABLE 3,Producer P2 details TABLE 3,Producer P1 details TABLE 3,Producer P3 details REGISTRY

32. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 32 Continuous Producer Servlet Registry Store location Lookup location Continuous Store table description Producer API SQL “CREATE TABLE” Result Set TableName Value 1Value 2 TableNameURLPredicate Schema TableNameColumn TableName Value 1Value 2 Insert TableName UKRALAlice Consumer ServletConsumer API SQL “SELECT” TableName Value 1Value 2 TableName Value 1Value 2 Query SQL “INSERT”

33. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 33 Query Types Continuous Latest History Static P1 TABLE 1,Producer P1 details TABLE 2,Producer P1 details TABLE 2,Producer P2 details TABLE 2,Producer P3 details TABLE 3,Producer P2 details TABLE 3,Producer P1 details TABLE 3,Producer P3 details REGISTRY

34. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 34 History or Latest Producer Servlet Registry Store location Lookup location Query Store table description Producer API SQL “CREATE TABLE” Result Set TableName Value 1Value 2 TableNameURLPredicate Schema TableNameColumn TableName Value 1Value 2 Insert TableName UKRALAlice Consumer ServletConsumer API SQL “SELECT” TableName Value 1Value 2 TableName Value 1Value 2 Query SQL “INSERT”

35. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 35 Query Types Continuous Latest History Static Latest Retention Period History Retention Period P1 TABLE 1,Producer P1 details TABLE 2,Producer P1 details TABLE 2,Producer P2 details TABLE 2,Producer P3 details TABLE 3,Producer P2 details TABLE 3,Producer P1 details TABLE 3,Producer P3 details REGISTRY P1 Latest-store Continuous&History-store

36. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 36 https://rgmasrv.ct.infn.it:8443/R-GMA

37. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 37 Security: Requirements R-GMA Consumer users: who requests information. Producer users: who provides information. Site administrators: who runs R-GMA services. Virtual Organizations: who “owns” the schema and registry. Consumer Provider Site Admin VO

38. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 38 Security: Solution R-GMA Consumer Provider Site Admin VO Mutual Autentication: guaranteeing who is at each end of an exchange of messages. Encryption: using an encrypted transport protocol (HTTPS). Authorization: implicit or explicit.

39. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 39 More information R-GMA overview page. –http://www.r-gma.org/http://www.r-gma.org/ R-GMA in EGEE –http://hepunx.rl.ac.uk/egee/jra1-uk/http://hepunx.rl.ac.uk/egee/jra1-uk/ R-GMA Documenation –http://hepunx.rl.ac.uk/egee/jra1-uk/LCG/doc/http://hepunx.rl.ac.uk/egee/jra1-uk/LCG/doc/

40. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 40 DGAS (Data Grid Accounting System)

41. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 41 Grid Accounting - Overview A generic Grid accounting process involves many phases that can be divided in: Metering: collection of usage metrics on computational resources. Accounting: storage of such metrics for further analysis. Usage Analysis: Production of reports from the available records. Pricing: Assign and manage prices for computational resources. Billing: Assign a cost to each user for his operations on the Grid. In this presentation we briefly describe these steps and give a quick overview of DGAS, the accounting middleware of the EGEE project.

42. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 42 Metering The metering phase in Grid accounting is probably the most important of the whole process. During this phase the user payload on a resource needs to be correctly measured, and assigned to the Grid User. Usage RecordThis requires the system collects information from the operating system (or the LRMS for batch jobs) and from the grid middleware. This information forms the Usage Record for the user process. This usage record must include at least the Grid Unique Identifier for the Grid User, the CEid as well as the JobID.

43. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 43 Metering (cont.) Usage Metering on Computing Elements is usually done by lightweight sensors installed on them. These sensors parse the LRMS event logs to build Usage Records that can be passed to the accounting layer.

44. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 44 Accounting Once collected, usage records need to be properly archived in databases for further analysis. These information should be available to the Users responsible for the payload, to the Site Managers of the Grid Resources and to the VO administrator of the user, but not to other people. In other words, information must be confidential. Usage records must be sent encrypted and signed by the Accounting Services.

45. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 45 Usage Analysis Information stored in the Accounting databases are rather complex. Not all the ‘users’ are interested in all of them. So there is the necessity for a system to analyses them and produce reports. Different types of users are interested in different views of the usage records, for example: A user will simply want to know how (s)he used the grid resources. A site manager needs to know who used its resources. A VO manager needs to trace what the VO users are doing on the Grid.

46. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 46 Pricing & Billing Resource owners may want to charge the users, so it is necessary to establish a cost for the service provided to the user. “A cost is usually computed according to a price assigned to the unit of usage of a computing resource and to the usage measured for the same resource.” Thus a service responsible for managing the resource prices and communicating them to all the partners is needed.

47. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 47 DGAS The Data Grid Accounting System was originally developed within the EU Datagrid Project and is now being maintained and re-engineered within the EU EGEE Project. The Purpose of DGAS is to implement Resource Usage Metering, Accounting and Account Balancing (through resource pricing) in a fully distributed Grid environment. It is conceived to be distributed, secure and extensible. DGAS system can be described using a three-layer model as shown in figure

48. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 48 DGAS Metering: Gianduia

49. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 49 The Home Location Register (HLR) service is the part of DGAS that is responsible for keeping the accounting information (usage records) for both grid resources and users. The usage records are used to define a job’s cost which can be debited to the user. In order to achieve scalability, accounting records can be stored on an arbitrary number of independent HLRs. At least one HLR per VO is foreseen, although a finer granularity is possible. DGAS Accounting

50. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 50 DGAS accounting architecture A simplified view of DGAS within the WMS context.

51. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 51 DGAS: Pricing & Billing Price Authority (PA) is a key component of the DGAS toolkit because it provides the features necessary for the Economic Accounting. The PA Server is an entity that assigns the prices to the resources. The prices, that are kept in a historic price database, can be assigned manually or using different dynamic pricing algorithms.

52. Enabling Grids for E-sciencE INFSO-RI-508833 4th EGEE Conference - Pisa, 23 October 2005 52 References ● Further information and documentation about DGAS can be found at:http://www.to.infn.it/grid/accounting/main.html