OGSIfication of
EDG’s R-GMA
31/5/2002
Steve Fisher / RAL
<s.m.fisher@rl.ac.uk>
People
• About 14 of us working on the system
• 4 of us here (if you wish to speak to us):
–
–
–
–
Abdeslem Djaoui
Steve Fisher
James Magowan
Manfred Oevers
• Thanks for input from:
– Steve Graham
– Peter Kunszt
– Wolfgang Hoschek
OGSIfication of R-GMA
Steve Fisher/RAL
2
R-GMA
Producer
subscribe
Registry
Consumer
OGSIfication of R-GMA
lookup
• Use the GMA from
GGF
• A relational
implementation
• Applied to both
information and
monitoring
• Creates
impression that
you have one
RDBMS per VO
Steve Fisher/RAL
3
Relational Approach
• Not a general distributed RDBMS system, but a way
to use the relational model in a distributed
environment where ACID properties are not generally
important.
• Producers announce: SQL “CREATE TABLE”
publish: SQL “INSERT”
• Consumers collect:
SQL “SELECT”
OGSIfication of R-GMA
Steve Fisher/RAL
4
R-GMA
Application Code
Consumer Servlet
Consumer
API
•
Registry
API
Registry Servlet
API – Servlet communication
– http(s) in
– XML back
Producer
API
Sensor Code
OGSIfication of R-GMA
Schema
API
Registry
API
Schema Servlet
ProducerServlet
“Event Dictionary”
Steve Fisher/RAL
5
Schema & Contributions
CPULoad (Global Schema)
Country
Site
Facility
Load
Timestamp
UK
RAL
CDF
0.3
19055711022002
UK
RAL
ATLAS
1.6
19055611022002
UK
GLA
CDF
0.4
19055811022002
UK
GLA
ALICE
0.5
19055611022002
CH
CERN
ALICE
0.9
19055611022002
CH
CERN
CDF
0.6
19055511022002
CPULoad (Producer 2)
CPULoad (Producer 1)
UK
RAL
CDF
0.3
19055711022002
UK
RAL
ATLAS
1.6
19055611022002
UK
GLA
CDF
0.4
19055811022002
UK
GLA
ALICE
0.5
19055611022002
CPULoad (Producer3)
OGSIfication of R-GMA
CH
CERN
ATLAS
1.6
19055611022002
CH
CERN
CDF
0.6
19055511022002
Steve Fisher/RAL
6
Contributions are Views
CPULoad (Producer 1)
UK
RAL
CDF
0.3
19055711022002
UK
RAL
ATLAS
1.6
19055611022002
SELECT * FROM
cpuLoad
WHERE country = ’UK’ AND site = ’RAL’
CPULoad (Producer 2)
UK
GLA
CDF
0.4
19055811022002
UK
GLA
ALICE
0.5
19055611022002
SELECT * FROM
cpuLoad
WHERE country = ’UK’ AND site = ’GLA’
OGSIfication of R-GMA
Steve Fisher/RAL
7
Our Scenario
S
a relational schema (for a virtual database)
q
queries posed against S
p
producers, associated with views on S
Currently views have the form:
SELECT
FROM
WHERE
*
r
< ??? >
The Mediator: how to match q with the p’s ?
OGSIfication of R-GMA
Steve Fisher/RAL
8
R-GMA
Application Code
Consumer Servlet
Consumer
API
•
Registry
API
Registry Servlet
API – Servlet communication
– http(s) in
– XML back
Producer
API
Sensor Code
OGSIfication of R-GMA
Schema
API
Registry
API
Schema Servlet
ProducerServlet
“Event Dictionary”
Steve Fisher/RAL
9
Step 1 - Isolate Servlets
Application Code
Consumer
API
•
Consumer
Instance
Registry
API
Registry
API – Servlet communication
– http(s) in
– XML back
Producer
API
Sensor Code
OGSIfication of R-GMA
Schema
API
Registry
API
Producer
Instance
Steve Fisher/RAL
Schema
“Event Dictionary”
10
Step 2 - Web Services
Consumer “Factory”
Application
Consumer
API
•
•
PortTypes
API – derived from WSDL
Web Services
Consumer
Instance
PortTypes
Registry
PortTypes
– WSDL, SOAP
•
Issues
– context to access instance
– HTTP Streaming
Producer
API
PortTypes
PortTypes
PortTypes
Producer
Instance
Sensor
Producer “Factory”
OGSIfication of R-GMA
Steve Fisher/RAL
Schema
“Event Dictionary”
11
Step 3 - OGSA
Application
Consumer
API
Producer
API
Sensor
•
•
•
•
•
Consumer
Factory
Consumer
Instance
Registry
Producer
Instance
Schema
Producer
Factory
All Grid Services
OGSA Factories, GSH, GSR
Registry includes HandleMapper
SQL as Service Data Element Query Language
lightweight api causes issues with lifetime management
– TerminationInterval then instance loopback to setTerminationTime.
OGSIfication of R-GMA
Steve Fisher/RAL
12
Other 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
• Security
– Authorisation looks hard
• Registry discovery
– same issues as OGSA in general
OGSIfication of R-GMA
Steve Fisher/RAL
13