EGEE Middleware: gLite Information Systems (IS) EGEE Tutorial ISGC 2008, Taiwan April 7, 2008

Agenda Introduction LDAP Glue Schema Architecture Practical Components: BDII, GIIS, GRIS Relationship Practical Querying Information System

Scope process User Interface Information System Resource Broker Submit job query Retrieve status & output create credential query publish state Submit job File and Replica Catalog Retrieve output Job status Logging Computing Element Storage Element Site X Job status process Authorization Service (VO Management Service) Logging and bookkeeping

How is Information Systems Used? Resource Discovery If you are a middleware developer Workload Management System: Matching job requirements and Grid resources Monitoring Services: Retrieving information about Grid Resources status and availability What resources are available to the Grid? Computing resources Storage resources Site and Services What is their current status? If you are a user Retrieve information about resources where you can run your job? where you can copy your files? If you are site manager or service You “publish” the information about the services you provide.

gLite: MDS Information System gLite adopted the Globus Monitoring and Discovery Service (MDS) architecture as it’s Information System The build blocks include LDAP protocol as the access protocol Glue Schema to define the format and information Architecture and Components GRIS GIIS BDII

Lightweight Directory Access Protocol Specialized service for reading, browsing and searching for information Consists of entries that describe objects has unique Distinguished Name (DN) with associated attributes and values Organizes entries as a tree: Directory Information Tree (DIT) Following a path from the node back to the root of the DIT Distinguished Name (DN) is built Uniquely identifier for entry “cn=Jane Doe,ou=ASGC,o=AS,c=TW,o=grid” o = grid (root of the DIT) c= TW c=US o = AS ou = ASGC CN = Jane Doe objectClass: person cn: Jane Doe phone: 5555666 office: R111

Glue Schema The data published in the Information System (IS) conforms to the Grid Laboratory Uniform Environment (GLUE) Schema. GLUE Schema is a common conceptual data model to describe Grid resources and defines: Structure of DIT: Hierarchy Entries and attributes Description of entries/attributes http://glueschema.forge.cnaf.infn.it/

Components of Information System Top-level BDII: collects information from GIISs At each site: a site GIIS (site BDII): collects information from local GRISs On each resource a GRIS (resource-level BDII): Publishes dynamic and static information BDII: Berkeley DataBase Information Index GIIS: Grid Index Information Server GRIS: Grid Resource Information Server Information Flow

GRISs, GIISs & BDII Relationship GOCDB User Application Resource Broker Monitoring Services BDII-A BDII-B Site A CE Site GIIS Site B CE Site GIIS Site C CE Site GIIS LFC Local GRIS CE Local GRIS SE Local GRIS SE Local GRIS RB Local GRIS CE Local GRIS CE Local GRIS SE Local GRIS MyProxy Local GRIS

Querying the IS Two sets of commands: lcg-infosites: simple, meets most needs lcg-info: supports more complex queries

lcg-infosites The lcg-infosites command can be used to query the information about existing Grid resources which support the given VO Simplest usage: lcg-infosites --vo <vo name> options Further information: lcg-infosites –h specify an VO name which the information to print is related indicate what information has to be printed

lcg-infosites options

PRACTICAL This introduces use of the commands to access the information system You will be exploring the GILDA grid, seeing what computing elements and storage elements exist Please go to the link for this practical http://homepages.nesc.ac.uk/~mjm/NA3ETF/Usage%20of%20lcg-infosites%20and%20lcg-info.htm

Instruction Prerequisites: Linux user background laptops with an ssh client (e.g. PuTTY ) PuTTY Download Page: http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html The following account can be used to log on the GILDA User Interface machines during the EGEE tutorial UI : glite-tutor.ct.infn.it or glite-tutor2.ct.infn.it (gLite 3.0) usernames : taipei01…taipei50 passwords : see tutorial sheet ALWAYS USE THE SAME ACCOUNT DURING ALL OF THIS EVENT – REMEMBER YOUR NUMBER!!