WP3 R-GMA: A Relational Grid information and monitoring system Steve Fisher / RAL 13/12/2002

WP3 Steve Fisher/RAL - 13/12/2002R-GMA2 Representing Heriot-Watt, Edinburgh –Andrew W Cooke, Werner Nutt IBM-UK –James Magowan, Manfred Oevers, Paul Taylor Queen Mary, University of London –Ari Datta PPARC –Rob Byrom, Steve Hicks, Laurence Field, Manish Soni, Antony J. Wilson, Xiaomei Zhu Rutherford Appleton Laboratory –Linda Cornwall, Abdeslem Djaoui, Steve Fisher SZTAKI, Hungary –Norbert Podhorszki Trinity College Dublin –Brian Coghlan, Stuart Kenny, David O’Callaghan, John Ryan

WP3 Steve Fisher/RAL - 13/12/2002R-GMA3 What is wrong with LDAP based solutions? Monitoring and information systems should be integrated –Information may be historical For monitoring With time stamps You may want information streamed to you –Subscribe to information There are very few hierarchies in the real world –Name a commercial HDBMS System should allow you to publish what you want –Current systems do not allow users to define and publish their own information System should allow you to find out what you want –LDAP tree has to be carefully designed to answer preconceived questions only

WP3 Steve Fisher/RAL - 13/12/2002R-GMA4 GMA From GGF Very simple model Does not define: –What registry looks like –How data are moved from Producer to Consumer –etc. Producer Consumer Registry Store location Lookup location execute or stream

WP3 Steve Fisher/RAL - 13/12/2002R-GMA5 Use the GMA from GGF A relational implementation Applied to both information and monitoring Creates impression that you have one RDBMS per VO Producer Consumer Registry Store location Lookup location execute or stream

WP3 Steve Fisher/RAL - 13/12/2002R-GMA6 Relational Approach Not a general distributed RDBMS system, but a way to use the relational model in a distributed environment where global consistency is not important. Producers announce:SQL “CREATE TABLE” publish:SQL “INSERT” Consumers collect:SQL “SELECT”

WP3 Steve Fisher/RAL - 13/12/2002R-GMA7 Not just one Producer DataBaseProducer –Relatively slow –Information not lost –Clean up strategy needed –No streaming (though could be defined in principle) –Supports joins StreamProducer –Fast –Uses an SQL parser – no RDBMs involved –Holds data in memory –Does not support joins –Can define minimum retention period

WP3 Steve Fisher/RAL - 13/12/2002R-GMA8 Not just one Producer ResilientProducer –Like the StreamProducer but won’t lose data if system crashes –So slightly slower LatestProducer –Just holds the latest information for any “primaryish” key –Supports joins

WP3 Steve Fisher/RAL - 13/12/2002R-GMA9 Canonical Producer Allows user defined code to be invoked to respond to SQL query Developed in collaboration with CrossGrid CP API User Code Canonical Producer Servlet Files CreateTable, Port, Protocol, Security, SQL Support, Multiple Query Support Security Insert Query Port Register

WP3 Steve Fisher/RAL - 13/12/2002R-GMA10 Producer Inheritance This is not visible to the user DataBaseProducer Cleanable Insertable Declarable APIBase Concrete Class (an example – some classes inherit from lower down) Supports clean up mechanism Allows rows to be inserted Allows tables to be declared Methods shared by all our APIs - e.g. disconnect()

WP3 Steve Fisher/RAL - 13/12/2002R-GMA11 Archiver (Re-publisher) It is a combined Consumer-Producer You just have to tell it what to collect and it does so on your behalf It will re-publish to any kind of “Insertable”

WP3 Steve Fisher/RAL - 13/12/2002R-GMA12 R-GMA: use of components BS Archiver of O-Z StreamProducer Archiver of I-N StreamProducer Archiver of A-H StreamProducer Smith (Wants to be told of each change of state of his job) Fitzwilliam (Wants to look at current state of all his jobs) Archiver of A-H LatestProducer Archiver of I-N LatestProducer Archiver of O-Z LatestProducer Consumer Each Bookkeeping Server publishes to a StreamProducer Archiver has a where clause to collect jobs belonging to a subset of users Most queries will be satisfied by one Archiver

WP3 Steve Fisher/RAL - 13/12/2002R-GMA13 A user application: CMS BOSS for job tracking on local farm –It currently forks the executable and parses stdout to publish info directly to an SQL DB –They publish to one table per job type and one table which is common to all job types They will try publishing via R-GMA instead –Providing a scaleable Grid solution

WP3 Steve Fisher/RAL - 13/12/2002R-GMA14 R-GMA for parallel applications GRM used to write a local file information on parallel applications PROVE displays this information GRM is being modified to use R-GMA for transport

WP3 Steve Fisher/RAL - 13/12/2002R-GMA15 Displays - Pulse A simple Java client

WP3 Steve Fisher/RAL - 13/12/2002R-GMA16 Command Line Looks rather like mysql command line Interactive or one command and quit

WP3 Steve Fisher/RAL - 13/12/2002R-GMA17 BrowserServlet JSP application some fixed common queries or compose your own

WP3 Steve Fisher/RAL - 13/12/2002R-GMA18 Displays - Nagios Looking to include Nagios as a presentation tool. Will write a Nagios plug-in to instantiate an Archiver and use that information to populate Nagios displays Can also benefit from Nagios alert mechanism Will have different configurations for Site, Country, whole Grid etc.

WP3 Steve Fisher/RAL - 13/12/2002R-GMA19 R-GMA from user perspective APIs in “all” languages –Java, C++, C, Python and Perl Easy installation and configuration –For developers –Installers –Users Highly portable (mostly Java) No dependence on other EDG software currently – but EDG security module is being integrated

WP3 Steve Fisher/RAL - 13/12/2002R-GMA20 R-GMA – How? Currently based on servlet technology –Tomcat –Multiple hand crafted APIs Java, C++, C, Python and Perl –Soft state registration –Uniform exception handling To ensure that useful messages and stack traces are preserved.

WP3 Steve Fisher/RAL - 13/12/2002R-GMA21 R-GMA API – Servlet communication –http(s) in –XML back Sensor Code Producer API Application Code Consumer API ProducerServlet Registry API Registry Servlet Schema API Schema Servlet Consumer Servlet Registry API

WP3 Steve Fisher/RAL - 13/12/2002R-GMA22 Schema & Contributions CPULoad (Global Schema) CountrySiteFacilityLoadTimestamp UKRALCDF UKRALATLAS UKGLACDF UKGLAALICE CHCERNALICE CHCERNCDF CPULoad (Producer 3) CHCERNATLAS CHCERNCDF CPULoad (Producer 1) UKRALCDF UKRALATLAS CPULoad (Producer 2) UKGLACDF UKGLAALICE

WP3 Steve Fisher/RAL - 13/12/2002R-GMA23 Contributions are Views CPULoad (Producer 1) UKRALCDF UKRALATLAS CPULoad (Producer 2) UKGLACDF UKGLAALICE SELECT * FROM cpuLoad WHERE country = ’UK’ AND site = ’RAL’ SELECT * FROM cpuLoad WHERE country = ’UK’ AND site = ’GLA’

WP3 Steve Fisher/RAL - 13/12/2002R-GMA24 The mediator Producers, associated with views on a virtual data base. Currently views have the form: –SELECT * FROM WHERE Queries posed against the virtual data base The Mediator must: –find the right Producers –combine information from them Can now merge information from several producers The final mediator will take “any” SQL statement and do the right thing The mediator is hidden inside the ConsumerServlet but is the component which makes R-GMA easy to use

WP3 Steve Fisher/RAL - 13/12/2002R-GMA25 Registry & schema distribution Will have one logical registry and schema per VO Each logical registry will have multiple physical “copies” Producer1 Registry1 Info mastered by Registry1 Copy of info from Registry2 Producer2 Registry2 Info mastered by Registry2 Copy of info from Registry1

WP3 Steve Fisher/RAL - 13/12/2002R-GMA26 Security Adding edg-security for authorisation –Gives secure socket factory for https Plan to use VOMS

WP3 Steve Fisher/RAL - 13/12/2002R-GMA27 OGSIfication Have recently started the migration to web and grid services –Apache axis –WSDL generated APIs –Will provide a wrapper for backwards compatibility

WP3 Steve Fisher/RAL - 13/12/2002R-GMA28 R-GMA - OGSIfication API – Servlet communication –http(s) in –XML back Sensor Code Producer API Application Code Consumer API ProducerServlet Registry API Registry Servlet Schema API Schema Servlet Consumer Servlet Registry API

WP3 Steve Fisher/RAL - 13/12/2002R-GMA29 Step 1 - Isolate Servlets API – Servlet communication –http(s) in –XML back Sensor Code Producer API Application Code Consumer API Registry Consumer Instance Registry API Registry API Producer Instance Schema API Schema

WP3 Steve Fisher/RAL - 13/12/2002R-GMA30 Step 2 - Web Services API – derived from WSDL Use SOAP Issue: HTTP Streaming Sensor Producer API Application Consumer API Registry Consumer Instance Producer Instance PortTypes Consumer “Factory” Producer “Factory” Schema PortTypes

WP3 Steve Fisher/RAL - 13/12/2002R-GMA31 All Grid Services OGSA Factories, GSH, GSR Registry includes HandleMapper SQL as Service Data Element Query Language Consumer Factory Producer Instance Step 3 - OGSA Sensor Producer API Application Consumer API Schema Registry Consumer Instance Producer Factory

WP3 Steve Fisher/RAL - 13/12/2002R-GMA32 OGSIfication issues Consider XML as internal representation of service data elements –Depends on other developments Consider Xquery as service data elements query language –Depends on how Xquery develops X-GMA ??

WP3 Steve Fisher/RAL - 13/12/2002R-GMA33 When? In the 24 th month of the project R-GMA still not deployed! Only bug fixes being made to EDG testbed To provide exposure and field testing are starting to deploy widely in the UK and in Italy

WP3 Steve Fisher/RAL - 13/12/2002R-GMA34 …and finally It is hard to make an efficient reliable distributed system without single points of failure and bottlenecks –This is probably not going to surprise anyone Most of next year will be spent on trying to achieve reliability and performance –rather than adding much new functionality Code is being developed under the EDG open source (BSD style) software license – –All contributions are most welcome