Information breakout
Things what we did
• What is the difference between a registry
and a catalog?
• What do we mean by naming?
• What does OGSA define?
• Using projects represented, try to
categorise and identify common themes
Naming and Registries
Project
OGSA-DAI
(OGSI)
Query
API
GT3 SGR +
XPath
Human
XML
DAIS
(WS-RF)
CIM + ?
GT3
Abstract
GT3
Address
GSH
Output
API
GT3
EPR inc
Referen
cePrope
rty
MDS2
(pre-WS)
MD4
(WS-RF)
rGMA
jGMA
EGEE DM
UDDI
LDAP
Globus
MDS
rGMA
API +
SQL
jGMA API
+ SQL
EGEE RLS
UDDI
GLUE
schema
XML
thing
GLUE
schema
GLUE
schema +
CIM
Logical
filenames
(EGEE)
Name +
Categorisation
+ taxonomies
LDAP
WS-RF,
WS-I
WSAgree
MySQL
JDBC /
XML:DB
?
e.g. UDDI4J
LDAP
map of
GLUE
schema
?
Table
GUID
TModel
(internal)
LDAP
WS-RF +
MySQL
JDBC
?
e.g. UDDI4J
UNIX
pathname
WS-RF
Referenc
eProperty
EPR +
extra
info
Endpoint
as URL
Physical
Filename
URL
rGMA
API
jGMA API
UDDI
Things to note (1)
• There is no reference framework to allow us to
compare our registries / catalogs
• The definition of the naming layers is confused
• The standards used by the implementations
seem to be based on when they were built
–
–
–
–
GLUE schema
LDAP
ServiceGroupRegistries
WS-RF
Things to note (2)
• No projects are using UDDI
– But ETF in UK is deploying UDDI for registering
services
– This is also the UK Grid Strategy
• We are moving towards using databases to
maintain persistence
• The GLUE Schema does not do everything
– Everyone has extended it to suit their purpose
• There needs to be a way of capturing what’s
good in GLUE+extns in CIM
Other things we should look at
• How do these groups define registries and
naming?
• DNS
• ebXML
• DAML
What specs past WS-I
• What is the split between registry and
catalogs?
• Naming
• Registry
• Catalogs
– UDDI
• Fine for static data
• Not good when you have high update rates
Registry
• WS-ServiceGroup
• WS-ResourceProperties
• WS-ResourceLifetime
– To define lifetime of entries?
• WS-Notification
– WS-BaseNotification
– WS-BrokeredNotification
– WS-Topics
• MDS uses:
– WS-ServiceGroup
– ResourceProperty
– ResourceLifetime
rehistry
• One registry may be used for many
purposes but
• Most have specific requirements
rGMA Registry
• Two registry functionalities
– Registry for metadata
•
•
•
•
•
•
Metadata about producers and consumers
Map attribute to an information source
Represented as GLUE Schema + extensions
Handles represented as URIs
Will be a WebService EndPoint
Update rate is very important
• SOAP over HTTP to do messages
Important Questions about
registries
• Where is data kept?
• How are the schemas defined?
• How are the interfaces defined?
• What’s important for the users of a registry?
• What do you use it for?
– Metadata
– Naming
• Is a catalog a registry which maps names?
• Jenny:
– RLS takes a logical name and maps to physical name
– MDC takes a set of attributes and maps it to a logical (physical)
name
• Discovery
– Finding something based on metadata
• OGSA defines naming in three levels
– Human defined name schemes
• Could include arbitary metadata
– Abstract name
• Probably unique
– Concrete Addresses
• The physical location
• OGSA-DAI
– ServiceGroupRegistry
– Resolve metadata information to
ServiceHandles
– No GSH->GSR mapping (abstract->physical)
because of GT3 “optimisation”
– Represented as DAIS specific schema
• Would like to map from metadata to
abstract names
WS-RF
• WS-Addressing + WSRenewableReferences defines a slightly
different two layers
DNS
• What can we learn from DNS?
MDS2
• Human Form – GLUE schema (“nodemem”)
• Abstract Form – LDAP mapping of GLUE
schema returns a Value (12.3.4.2.infohostname)
• Address – Fully qualified name (e.g. of
attached disk)
DAIS2
• Human – “My genome db”
• Abstract – URN: dais://12345
• Address – WS-RF: EPR +
ResourceProperty