gLite Information System

www.eu-eela.org

E-infrastructure shared between Europe and Latin America

12th EELA Tutorial for Users and System Administrators

gLite Information SystemYubiryn Ramírez

ULA - Mérida

12th EELA Tutorial Users

Lima, 24.09.2007

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Lima, 12th EELA Tutorial, 24.09.2007

This presentation is based on previous

gLite presentations

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• How to discover resource?• Grid Information System• Glue Schema• gLite LCG Information System

– Hierarchy– LDAP model

• RGMA– Overview– Server Architecture– Consumer-Producer model– RGMA Concepts

• References

Outline

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How to discover resource?

• 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).

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• What is?– System to collect information on the state of resources

• Why?– To discover resources of the grid and their nature– To have useful data in order to who is in charge of managing

the workload to do it more efficiently.– To check for health status of resources.

• How?– Monitoring state of resources locally and publishing fresh data

on the information system.– Adopting a data model that MUST be well known to all

components that want to access monitored information

Grid Information System Overview

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• About Measures– Measures SHOULD be sensitive to the aim the users want to achieve.– Measures SHOULD be enough accurate to be considered valid.– Rate of taking measures MUST be adequate to be used.

• About the gathering of Information– How and when collected info should be published?– Where should collected info be stored?– How long should this info be maintained in the storage?

• Querying the Information System– Where should queries be sent to have a response?– What syntax and protocols have to be adopted to make queries?– What is the adopted data model to describe resources?

• Security– Who is allowed to execute queries against the IS and what type of

queries is he allowed to do?– Management of user rights and credentials.

Designing of Information System

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• Basic data model.– Grid Laboratory Uniform Environment (GLUE) Schema.

• Two architectures in glite3– LCG Information System

BDII over Globus MDS. OpenLDAP interface. Preserves LCG-2 compatibility.

– Relational Grid Monitoring Architecture (R-GMA) Based on the GMA standard from the Grid Global Forum Information in SQL relational databases Web Services. Future replacement of LCG IS.

gLite Information System

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GLUE Schema

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• A schema of objects and attributes describing Grid resources and its relationships.– Originally a EU-DataTAG and US-iVDGL coordinated effort. – Current participants: EGEE, OSG, Globus and NorduGrid. – A way to describe Grid info

Statically and dynamically supplied Hierarchically represented Independently of the framework (LDAP, XML, SQL…)

• Actual release (1.2) is mapped into– LDAP– XML– Old ClassAd (used by Condor Matchmaking

Glue Schema

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Site

A collection of resources owned by the same organization and managed by the same administrator. Contains info on the location, the administrator, the web homepage and so on.

Service

The description of a deployed Web Service. Contains the URI endpoint of the WS, the WSDL document, the list owners and so on.

StorageElement Cluster

1 1 1

*

*

*

Site Element

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Computing Element

ComputingElement

Abstraction of a queue of jobs

Policy

Contains info on configuration policies. MaxWallClockTime, MaxRunningJobs, MaxCPUTime . . .

AccessControlPolicyBase

Set of rules defining access control policy rules

Info

Static information on the resource that deal with the type of Loca scheduler adopted, the default Storage Element and so on.

VOview

View for a given Virtual Organization. Contains authorization details for VO members and the amount of available resources.

State

Dynamic information on the status of this queue such as the number of free CPUs and the Estimated Traversal Time (ETT)

Job

Information on jobs in this queue, its owner, its local and global ID and its status

*

*

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LCG Information System

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• Resource level: Grid Resource Information Server (GRIS)

– One GRIS on top of each CE, SE, RB, MyProxy (no WNs).

– Sensors and scripts get status of concrete resources statically (e.g. GlueCEUniqueID) or dynamically (e.g. GlueCEStateWaitingJobs)

LCG Information System Levels

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• Site level: Grid Index Information Server (GIIS)

– Compiles all the information of the different GRISes in a site.

– LCG-2 recommends using a BDII instead of a GIIS Improves robustness and stability. Called the site BDII


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• Top level: Berkeley DB Information Index (BDII)

– Keeps all Grid information about the VOs (generally only one). – Stores information from local BDIIs or GIISes in its database. – Only queries sites that are included in a configuration file.


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LCG Information System Hierarchy

GIISINFN sez. CT

GIISMerida (gilda)

GRISes GRISes

Other GIIS (gilda)

GRISes

BDII (gilda)

BDII

Globus MDS

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• Way of collecting info– Pull model (higher level servers periodically query lower level

servers)– All servers are based on LDAP

Inherit hierarchical structure (tree-like) LDAP Data Information Format (LDIF)

• Users get info with– Generic applications

ldapsearch (MDS: 2135 and BDII:2170 ports) Graphical (BDII web; LDAP GUIs) Always can get information about specific resources (maybe

more up-to-date) by querying directly the site BDIIs, GIISes or GRISes.

– Querying VO info with lcg-infosites or lcg-info

LDAP Model

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LDAP Browser show BDII information

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R-GMA

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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) standart from the Global Grid Forum (GGF).

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R-GMA Overview

• Information in SQL relational databases (a DB per VO)• Query syntax is a SQL subset• Simple consumer-producer model• Web Services oriented• CLI and Web user interface• Allows self-logging applications• Future replacement of LCG IS

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R-GMA Overview

• R-GMA offers a global view of the VO information– In one large relational DB: virtual database.– Registry stores localization tuples (database rows) published by

producers: Standard Tables: CE state in GLUE Schema (by R-GMA-GIN) Applications specific tables (e.g. self-logging with Log4j) Access by SQL queries through a WS interface.

– Always updated Consumers get information directly from the resource Can be cached by a secondary producer from single o

multiple producers to improve access.

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R-GMA Server Architecture

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R-GMA Server Description

• R-GMA Servers

– Server (one or several)

– Schema Server (There is one common global schema server for the grid)

– Registry Server (one or several)

– Browser (shows grid information via web browser)

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R-GMA Server Description

R-GMA Clients

– Generic Client (generic set of APIs for different languages and CLIs)

– Servicetool (used by all services to publish its existence and status)

– Site Publisher Client to publish the existence of a site. Each site must have one R-GMA site publisher.

– GadgetIN (GIN) Client to extract information from MDS and to republish it to R-GMA. used by the CE.

– Data archiver (flexible archiver) Client to make the data that is coming from the R-GMA site-publisher,

servicetool and GIN constantly available. By default the GLUE tables and service tables are archived, however this

can be configured.

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R-GMA Server per Node Type

– The gLite R-GMA Server should deployed the first as part of a gLite grid, because all services require it to publish service information.

Deployment module Contains Used / included by

R-GMA Server R-GMA server

R-GMA registry server

R-GMA schema server

R-GMA browser

R-GMA site publisher

R-GMA archiver

R-GMA servicetool

MON-box

R-GMA client RGMA client APIs UI, WN, SD

R-GMA servicetool R-GMA servicetool R-GMA server,VOMS, LB, WMS, CE, DC, FTS, FTA, Hydra, I/O-Server,Torque Server

R-GMA GIN R-GMA GadgetIN CE

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RGMA Producer – Consumer model

PRODUCER

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. CONSUMER

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RGMA Multiple Producers

• The Consumer will get all the URLs that could satisfy the query.

• The Consumer will connect to all the Producers.

• Producers that can satisfy the query will send the tuples to the Consumer.

• The Consumer will merge these tuples to form one result set.

Consumer

Producer 1

Registry

TableName

Value 1 Value2

Value 3 Value 4

TableName

Value 1 Value 2

TableName URL 1

TableName URL 2

Producer 2TableName

Value 3 Value 4

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Select * from CPULoad

CPULoad (Producer 3)

CH CERN ATLAS 1.6 19055611022002

CH CERN CDF 0.6 19055511022002


UK RAL CDF 0.3 19055711022002

UK RAL ATLAS 1.6 19055611022002


UK GLA CDF 0.4 19055811022002

UK GLA ALICE 0.5 19055611022002

CPULoad (Consumer)

Country Site Facility Load Timestamp

UK RAL CDF 0.3 19055711022002

UK RAL ATLAS 1.6 19055611022002

UK GLA CDF 0.4 19055811022002

UK GLA ALICE 0.5 19055611022002

CH CERN ALICE 1.6 19055611022002

CH CERN CDF 0.6 19055511022002

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Joins

Service

URI VO type emailContact site

gppse01 alice SE [email protected] RAL

gppse01 atlas SE [email protected] RAL

gppse02 cms SE [email protected] RAL

lxshare0404 alice SE [email protected] CERN

lxshare0404 atlas SE [email protected] CERN

ServiceStatus

URI VO type up statusgppse01 alice SE y SE is running

gppse01 atlas SE y SE is running

gppse02 cms SE n SE ERROR 101

lxshare0404 alice SE y SE is running

lxshare0404 atlas SE y SE is running

Result Set (Consumer)

URI emailContact

gppse02 [email protected]

SELECT Service.URI Service.emailContact FROM Service S, ServiceStatus SS WHERE (S.URI= SS.URI and SS.up=‘n’)

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R-GMA Concepts

• Producers– Primary producer

The producer creates and stores locally the informatiion– Secondary producer

The producer stores locally the information coming from primary producers

– On DemandThe producer returns the information only under the request of the consumer

• Consumer– Continuous

As soon as new data becomes available it is broadcast to all interested parties

– LatestCorresponds to the intuitive idea of “current information”

– History– Returns time sequenced data

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• LCG-2 User Guide– https://edms.cern.ch/file/454439//LCG-2-UserGuide.html

• R-GMA overview page.– http://www.r-gma.org/

• R-GMA in EGEE– http://hepunx.rl.ac.uk/egee/jra1-uk/

• R-GMA Documenation– http://hepunx.rl.ac.uk/egee/jra1-uk/glite-r1/

• GLUE Schema– http://infnforge.cnaf.infn.it/glueinfomodel/

References

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Questions …

Documents

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