1. gLite Information System
The EPIKH Project
(Exchange Programme to advance e-Infrastructure Know-How)
gLite Information System
Hui Wang Sino-German Joint Software Institute, BUAA
Hello, everyone,
I’m Wang Hui from Sino-German Joint Software Institute, Beihang University
Today I’m going to talk about gLite Information System

2. Outline Introduction Background LDAP BDII R-GMA Monitoring Conclusion
GLUE Schema
LDAP
BDII
R-GMA
Monitoring
Conclusion
Here is the outline, let’s start

3. Introduction
first, I want to introduce what is the gLite Information System, and why we need it

4. gLite Components
here are the gLite Components, some of them are grouped to providing services such as data services, security services, access services, job management services.
and Information && Monitoring services which we will focus on in this presentation.

5. gLite Components worker node
just as this slide shows, in gLite, the BDII collect the information from computing element and storage element,
and using those information to discover resources and their properties. check the resources’ health status. and provide data in order to manage the workload more efficiently
worker node

6. The Information System
What?
System to collect information on the state of resources
Why?
To discover resources of the grid and their properties
To check for health status of resources
To provide data in order to manage the workload more efficiently
How?
Monitoring and publishing fresh data on the state of resources
Adopting a well known data model
so the gLite Information System is a system to collect information on the state of resources
and why we need the information system?
they are many reasons, just as we described before, …
you see the information system is very important, but how we can implement it?

7. Who and how use the IS Users Site Managers Middleware
Retrieve information about resources:
Where can I run my job?
Where can I store my files?
Which software packages are available on a give CE?
Site Managers
Publish information about the resources and services they provide
Middleware
WMS: matching job requirements and allocating the resources
Monitoring Services: retrieving information about the status and availability of resources
the Information System is useful, with the Information System
Users can …
Site Managers can …
and Middleware can …

8. Information Services The gLite Data Model uses GLUE Schema
Two information system available in gLite: BDII and R-GMA
The Berkeley DB Information Index (BDII)
has been the LCG middleware Information System provider
is an evolution of Globus Meta Directory System (MDS)
is based on Lightweight Directory Access Protocol (LDAP) servers
The Relational Grid Monitoring Architecture (R-GMA)
is an implementation of the Grid Monitoring Architecture (GMA) standardized by the Open Grid Forum (OGF)
is a relational implementation of the GMA
is strongly Web Service Oriented
GLUE stands for Grid Laboratory Uniform Environment, which is used to describe the Grid Resources Information stored in the Information Systemv
There are two information system available in …

9. Background
now we will talk background of the gLite information system

10. Why an Information schema is required?
Resources are heterogeneous, geographically dispersed and span multiple trust domains
Resources can be dynamically contributed by different owner institutions
a precise and shared description of resources among information consumers and resource providers is necessary
The same resources description has to be readable from different Grid infrastructures to allow interoperability among them
we have talked before, gLite Information system using GLUE schema, but why an information schema is required?
there are three reasons, the first…
and the second…
third…

11. LDAP Overview
It is a protocol that defines the method by which directory data is accessed
Optimized for reading, browsing and searching information (write-once-read-many-times service)
Data is represented as a hierarchy of objects (entities) forming a tree structure
Data Information Tree (DIT)
BDII is based on a LDAP, LDAP stands for Lightweight Directory Access Protocol
hierarchy ['haiə,rɑ:ki]
which we call it Data Information Tree

12. LDAP Overview Distinguished Name (DN) Attributes Types
Unique name that unambiguously identifies an entry
Es. dn: o=INFN,c=Italy,dc=grid
Attributes Types
dc=grid
(root of the DIT)
c=Italy
c=India
c=China
o=INFN
Meaning
Attribute
Domain Component DC
Country Name C
Organization Name O
Organization Unit Name OU
Common Name CN
ou=Roma
LDAP using Distinguished Name to identifies an entry, the Distinguished Name is unique and unambiguously.
it have some attributes types, DC for Domain Component, C for Country Name
here is a example for the data information tree, the root of the Data Information Tree is the Domain Component which is named “grid”, and below is the Country Name, China, Italy and India. then the Organization Name follows, Infn, then is
the Organization Unit Name and Common Name.
using the Distinguished Name can unique identify an entry
ou=Catania
cn=Riccardo Rotondo

13. LDAP Referrals An LDAP server can store a partial DIT
To obtain the DIT all servers need to be linked together
LDAP 1 server
LDAP 2 server
LDAP 3 server
c=USA,dc=example
o=IBM,c=USA,dc=example
dc=example
c=USA
c=USA
o=IBM
o=IT
ou=WEB
An LDAP server can store a partial DIT, if you want to obtain the Data Information Tree, all the LDAP servers need to be linked together.
here is a example to explain how it works, when a client request a entry with this Distinguished Name, it first access the global directory LDAP server which is the root of the Data information tree, dc = example, then refer to the USA LDAP server, and the IBM LDAP server …
So all the …
referral
referral
All client requests have to start at the global directory LDAP 1

14. BDII
since we have know about the background, lets explain the BDII

15. GRISs, local BDII and BDII
Each site can run a BDII, it collects the information from local BDIIs
and local BDII collects the information given by the GRISs
local GRISes run on Computing Elements and Storage Elements and report dynamic and static information

16. gLite IS Architecture
it’s a hierarchical structure, resource-level BDII provide information to the site-level BDII, and site-level BDII provide information to the top-level BDII

17. The BDII LDIF = LDAP Data Interchange Format
The Berkeley Database Information Index (BDII) consists of a standard LDAP database which is updated by an external process. The update process obtains LDIF from a number of sources and merges them. It then compares this to the contents of the database and creates an LDIF file of the differences. This is then used to update the database.

18. LDAP Clients BDII servers use standard LDAP protocols
All LDAP client are to access BDII information
Command line or graphical application for every OS are available to access an LDAP server
Ldapsearch –xxx –h [hostname]-p 2170 –b mds-vo-name=local,o=grid

19. LDAP Overview gLite provides several tools to manage the IS
Two gLite commands in the UI for the IS queries:
lcg-infosites: shows some information related to a Grid component
lcg-info: supports complex queries to retrieve more specific information
variare

20. RGMA

21. RGMA overview
R-GMA is based on Grid Monitoring Architecture (GMA) standard defined by the OGF
Implements a Consumer-Producer model
Information are stored in a SQL relation database using a virtual DB per VO
Information are always updated because the consumer get information directly from the provider
Users can query information using a subset of the SQL
Web service oriented
CLI and Web user interface
Relational Grid Monitoring Architecture

22. R-GMA Producer-Consumer Model
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 to listen for new data
Data flows directly from the Producer to the Consumer

23. Monitoring

24. Monitoring Several centralised monitoring systems avialable
Official monitoring are:
Gridmap managed by CERN at
Gstat managed by Academia Sinica at
Grid Reat Time Monitoring byt Imperial College London at
variare

25. Gridmap
variare

26. GStat
variare

27. Real Time Monitor
variare

28. Conclusion

29. Conclusion
Two Information System are provided by gLite: BDII and R-GMA
Information are organised following the GLUE Schema
Users can contact the tob BDII in the hierarchy to get the information of all the resources
Current implemenation use only BDII to check the state of the resources

30. Thank you for your kind attention !
Any question?
Special Thanks to Fabrizio Pistagna for the material