1. OGSA Information Abdeslem Djaoui OGSA Information, OGSA-WG #11
30 June, 2005 (GGF14 in Chicago) 7:30-9:00am

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3. OGSA Information introduction and status RSS – relation to OGSA Info
Session Agenda
Housekeeping
GGF IP
Signing sheet
Note taker
OGSA Information introduction and status
Abdeslem Djaoui
RSS – relation to OGSA Info
Mathias Dalheimer
OGSA Information architecture skeleton

4. OGSA Information Introduction and Status

5. OGSA Information V1.0 and beyond
Set of scenarios
Wide range of capabilities
Naming
Discovery
Monitoring
Message delivery
Logging
Since then
Naming just moved to its own WG
Logging BOF at GGF12, but no current activity
Since GGF13
OGSA-F2F
Work on InfodD specification

6. So What do we mean by OGSA information?
The term is used generically to refer to
Any data used for the following:
Discovery
Monitoring
Such data relates to:
Resources (storage, networks, …)
Grid Services
Grid Applications
OGSA-Info capabilities allow for
moving information around (message delivery)
“matching” of sources and sinks of that information
Defining new types of information
Exact meaning of that information is dependent on the usage (logging, monitoring, auditing, …), but underlying capabilities are the same

7. OGSA-Info – one cloud
Client publishers use OGSAProducer interface to publish information
Client consumers use OGSAConsumer interface to request and receive information
Information from Publishers is dynamic and scattered throughout the Grid
Publishers and consumers do not necessarily know about each other before hand
Client
Publisher
Client
Publisher
OGSAProducer
OGSAProducer
OGSA-Information
OGSAConsumer
OGSAConsumer
Client
Consumer
Client
Consumer

8. Advantages OGSA Producer/Consumer interfaces
Provide a simple and common way for users to put information into the Grid and to retrieve information from the Grid
Hide complexity of information system from end-users
Abstract differences between available specification
Example: WSN Consumer and InfoD Consumer
For consumers it creates impression that you have one “Virtual” data base which they can query through OGSAConsumer interface
How this is achieved is being worked out in InfoD

9. Typical Consumer Queries
“For every node N, how many computers connected to N have currently a cpu-load of no more than 30%?”
“Yesterday, between which nodes was the average transportation time for 1 MB packets higher than than 0.… seconds?”
“Show me the (average) cpu-load of computers at CERN and RAL!”

10. Combined Consumer/Publisher - CCP
Used to consume and then re-publish data
To co-locate information to speed up queries
To reduce network traffic
To use different publisher properties P
CCP OC OP P OC OC P
P – Publisher
OC – OGSAConsumer
OP - OGSAProducer

11. Some requirements – Publishers and Producers
Publishers have no prior knowledge of potential consumers
Producers may have different properties/QoS.
Persistency
Retention period
Delivery guarantees
The information system should not impose limits on the number of publishers
Monitoring data should carry a timestamp
A user must be able to publish data (via a Producer) even if the type of this data is not previously known to the system
Critical data needs to be secured

12. Some requirements - Consumers
Consumers have no prior knowledge of relevant producers
Consumers may have different properties/QoS.
Persistency
Retention period
Delivery guarantees
The information system should not impose limits on the number of consumers
A Consumer should be able to obtain information from a Publisher on a one off basis or as a stream
Critical data needs to be secured
A consumer should return an answer within an acceptable amount of time

13. Relation of information services to rest of OGSA
leverage OGSA infrastructure
Basic Profile
Be leveraged
For Discovery purposes
By Execution Management Services
By problem determination services
By resource reservation services
By resource usage services
By application monitoring services

14. RSS - Mathias

15. OGSA Info architecture skeleton

16. Approach 1: The Data Warehouse
Straight forward:
store all data about the Grid status into a huge database or file or …
and query it
Not realistic:
Loading takes time
Data occupy space
Connections to the warehouse may fail
Often information flows as data streams, and queries ask for data streams as output

17. Approach 2: A “Virtual” distributed data warehouse
The Grid Monitoring Architecture (GMA) of the Global Grid Forum distinguishes between:
Distributed Consumers of information
Distributed Producers of information
Directory Service
Producers register their supply
Consumers register their demand
Consumer
Producer
Monitoring- Application
Data Base
Sensor
Directory Service
find/ register
GMA separates matching of consumers to producers and delivery of data from producers to consumers

18. Vocabulary management questions
In which language do producers register their supply and consumers their demand
XML, Xpath, Xquery
Relational, SQL??
Domain specific??
How to create and delete types of publications dynamically
How to create new vocabularies and how to advertise and discover them
Are Vocabulary transformations supported
Synchronization

19. An example implementation - Relational Grid Monitoring Architecture
Publish Tuples
Producer
application
Producer
Service
Register
SQL “INSERT”
Registry
Service
Query
Tuples
SQL “SELECT”
Locate
Mediator
Send Query
Consumer
application
Consumer
Service
Receive Tuples
SQL “CREATE TABLE”
Schema
Service
Vocabulary
Manager
An implementation of the GGF Grid Monitoring Architecture (GMA)
All data modelled as tables: a single schema gives the impression of one virtual database for VO

20. R-GMA Registry/Schema: A Virtual Data Warehouse enabler
Language of producers and consumers: relational queries (SQL)
Vocabulary: Relations in a global schema
Consumer
DB-Producer
Global Schema S DB
Stream Producer
Sensor
V1 V Vn V
Views on S
Registry
Query
Consumer: poses queries over global schema
Producer:
has a type (stream p., database p.)
publishes relations R1, … ,Rk
for every R, registers a simple view V on the global schema

21. Pub/Sub model WSN Infrastructure Producers Consumers Subscribers
Publishers
Combined Consumers/Publishers
Topics

22. INFOD pushes the envelop by
Beyond WSN - INFOD
INFOD pushes the envelop by
Specifies an ObjectRegistry (GMA directory)
Supports matching of publishers and consumers
Allows definition of publication Type schema (Simple Vocabulary Management)
Allows more than one Vocabulary
Vocabularies are domain specific (R-GMA, NextGrid, SensorNet, …)
More control on the publisher side
Support creation of messages based on events or even state changes
Support publishers in the dissemination of messages
Allows subscribers to have more control of what is published

23. INFOD Message Creation
Publishers
States
Events
Messages
State changes can cause events which in turn can cause messages to be produced which are then delivered to consumers
Not all publishers allow to control the creation of messages based on events or even state
Consumers

24. Summary
OGSA information services address the following basic capabilities:
p/c matchmaking
message delivery
Elementary Vocabulary management
Additional capabilities are layered (extend) or composed on top of OGSA info
OGSA-Info need to address
Common interface independent of implementation
Either use or abstract existing interfaces from InfoD and WSN
Syntactic interoperability
Standard or common schema/vocabulary
Semantic interoperability

25. How to materialize this architecture skeleton
Need participation from grid projects
To produce architecture document
Some open Issues: registry/Schema replication, federation, p2p, fine-grained authorization, ….
Important to reach consensus on Producer/Consumer interfaces taking into account InfoD and WSN
Interface to Schema and ObjectRegistry services?
Join OGSA-WG Information design team
Send to OGSA-WG or
Join InfoD WG