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

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

3. 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

4. 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.

5. 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

6. 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:
office: R111

7. 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

8. 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

9. 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

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

11. 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

12. lcg-infosites options

13. 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

14. Instruction Prerequisites:
Linux user background
laptops with an ssh client (e.g. PuTTY )
PuTTY Download Page:
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!!