Globus Toolkit Futures: An Open Grid Services Architecture Ian Foster Carl Kesselman Jeffrey Nick Steven Tuecke Globus Tutorial, Argonne National Laboratory,

Globus Toolkit Futures:An Open Grid Services

Architecture

Ian Foster

Carl Kesselman

Jeffrey Nick

Steven Tuecke

Globus Tutorial, Argonne National Laboratory, January 29, 2002

April 18, 2023 Open Grid Services Architecture 2

The Grid World: Current Status Dozens of major Grid projects in scientific &

technical computing/research & education Considerable consensus on key concepts and

technologies– Open source Globus Toolkit™ a de facto standard for

major protocols & services

– Far from complete or perfect, but out there, evolving rapidly, and large tool/user base

Industrial interest emerging rapidly Opportunity: convergence of eScience and

eBusiness requirements & technologies


Overview

eBusiness requirements and the need for a services-based model– Jeff Nick, IBM

Open Grid Services Architecture overview– Ian Foster

Grid service specification & demonstration of OGSA prototype– Steven Tuecke

Open Grid Services ArchitectureOverview & Globus Toolkit Evolution

Ian Foster

Mathematics and Computer Science Division

Argonne National Laboratory

and

Department of Computer Science

The University of Chicago


The Grid Problem

Resource sharing & coordinated problem solving in dynamic, multi-institutional virtual organizations


Why Grids? (1) eScience A biochemist exploits 10,000 computers to

screen 100,000 compounds in an hour 1,000 physicists worldwide pool resources for

peta-op analyses of petabytes of data Civil engineers collaborate to design, execute,

& analyze shake table experiments Climate scientists visualize, annotate, &

analyze terabyte simulation datasets An emergency response team couples real time

data, weather model, population data


Why Grids? (2) eBusiness Engineers at a multinational company

collaborate on the design of a new product A multidisciplinary analysis in aerospace

couples code and data in four companies An insurance company mines data from partner

hospitals for fraud detection An application service provider offloads excess

load to a compute cycle provider An enterprise configures internal & external

resources to support eBusiness workload


Intelligent Infrastructure:Distributed Servers and Services


The Grid World: Current Status Dozens of major Grid projects in scientific &

technical computing/research & education Considerable consensus on key concepts and

technologies– Open source Globus Toolkit™ a de facto standard for

major protocols & services

– Far from complete or perfect, but out there, evolving rapidly, and large tool/user base

Industrial interest emerging rapidly Opportunity: convergence of eScience and

eBusiness requirements & technologies


Globus Toolkit: Evaluation (+)

Good technical solutions for key problems, e.g.– Authentication and authorization

– Resource discovery and monitoring

– Reliable remote service invocation

– High-performance remote data access This & good engineering is enabling progress

– Good quality reference implementation, multi-language support, interfaces to many systems, large user base, industrial support

– Growing community code base built on tools


Globus Toolkit: Evaluation (-) Protocol deficiencies, e.g.

– Heterogeneous basis: HTTP, LDAP, FTP

– No standard means of invocation, notification, error propagation, authorization, termination, …

Significant missing functionality, e.g.– Databases, sensors, instruments, workflow, …

– Virtualization of end systems (hosting envs.) Little work on total system properties, e.g.

– Dependability, end-to-end QoS, …

– Reasoning about system properties


“Web Services” Increasingly popular standards-based framework for

accessing network applications– W3C standardization; Microsoft, IBM, Sun, others

WSDL: Web Services Description Language– Interface Definition Language for Web services

SOAP: Simple Object Access Protocol– XML-based RPC protocol; common WSDL target

WS-Inspection– Conventions for locating service descriptions

UDDI: Universal Desc., Discovery, & Integration – Directory for Web services


The Need to SupportTransient Service Instances

“Web services” address discovery & invocation of persistent services– Interface to persistent state of entire enterprise

In Grids, must also support transient service instances, created/destroyed dynamically– Interfaces to the states of distributed activities

– E.g. workflow, video conf., dist. data analysis Significant implications for how services are managed,

named, discovered, and used– In fact, much of our work is concerned with the

management of service instances


Open Grid Services Architecture Service orientation to virtualize resources From Web services:

– Standard interface definition mechanisms: multiple protocol bindings, multiple implementations, local/remote transparency

Building on Globus Toolkit:– Grid service: semantics for service interactions

– Management of transient instances (& state)

– Factory, Registry, Discovery, other services

– Reliable and secure transport Multiple hosting targets: J2EE, .NET, “C”, …


OGSA Service Model System comprises (a typically few) persistent

services & (potentially many) transient services All services adhere to specified Grid service

interfaces and behaviors– Reliable invocation, lifetime management,

discovery, authorization, notification, upgradeability, concurrency, manageability

Interfaces for managing Grid service instances– Factory, registry, discovery, lifetime, etc.

=> Reliable, secure mgmt of distributed state


The Grid Service A (potentially transient) Web service with specified

interfaces & behaviors, including– Creation (Factory)

– Global naming (GSH) & references (GSR)

– Lifetime management

– Registration & Discovery

– Authorization

– Notification

– Concurrency

– Manageability


Factory

A Grid service with Factory interface can be requested to create a new Grid service instance– Reliable creation (once-and-only-once)

Create operation can be extended to accept Grid-service-specific creation parameters

Returns a Grid Service Handle (GSH)– A globally unique URL

– Uniquely identifies the instance for all time

– Based on name of a home mapper service


Mapper A GSH is a stable name for a Grid service, but does

not allow client to actually communicate with the Grid service

A Grid Service Reference (GSR) is a WSDL document that describes how to communicate with the Grid service– Contains protocol binding, network address, …

– May expire (I.e. GSR information may change) The Mapper interface allows a client to map from a

GSH to a GSR– http get on GSH also returns a GSR


Lifetime Management GS instances created by factory or manually;

destroyed explicitly or via soft state– Negotiation of initial lifetime with Factory

SoftStateDestruction interface supports– GetTerminationTime message for inquiry

>Notification interface also allows for lifetime notification

– SetTerminationTime message for keepalive Soft state lifetime management avoids

– Explicit client teardown of complex state

– Resource “leaks” in hosting environments ExplicitDestruction interface also available


Discovery A Grid service instance may maintain a set of

service information– XML fragments encapsulated in standard <name,

type, TTL-info> containers Discovery interface allows clients to query the

Grid service instance for this information– Query operation, plus supporting operations

> Extensible query language support

See also Notification interfaces– Allows notification of service existence and about

service information


Registry

The Registry interface may be used to discover a set of Grid service instances– Returns a WS-Inspection document containing the

GSHs of a set of Grid services

– Also returns policy associated with the set

– Also available through Discovery interface The RegistryManagement interface allows for

soft-state registration of a Grid service– A set of Grid services can periodically register their

GSHs into a registry service, to allow for discovery of services in that set


Authorization

Protocol binding handles authentication during invocation of Grid service operation– Gives service URI for authenticated subject

Grid service instance should apply authorization policy on all operations– May be site-, service-, instance-, etc., specific

OGSA defines standard interfaces for remote management of access control policy– OperationAuthorizationManagement

– SubjectEquivalency


Notification Interfaces NotificationSource for client subscription

– One or more notification generators> Generates notification message of a specific type

> Typed interest statements: E.g., Filters, topics, …

> Supports messaging services, 3rd party filter services, …

– Soft state subscription to a generator NotificationSink for asynchronous delivery of

notification messages A wide variety of uses are possible

– E.g. Dynamic discovery/registry services, monitoring, application error notification, …


Using OGSAto Construct Grid Environments

Factory RegistryService

FactoryH2R

Mapper

ServiceService Service ...

...

(a) Simple HostingEnvironment

Factory RegistryService

FactoryH2R

Mapper

ServiceService Service ...

...

F R

F M

SS S

F R

F M

SS S

(b) Virtual HostingEnvironment

E2EFactory

E2E Reg

E2E H2RMapper

...

F1

R

M

SS S

F2

R

M

SS S

E2E S E2E S E2E S

(c) Compound Services

In each case, Registry handle is effectively the uniquename for the virtual organization.


OGSA and the Globus Toolkit Technically, OGSA enables

– Refactoring of protocols (GRAM, MDS-2, etc.)—while preserving all GT concepts/features!

– Integration with hosting environments: simplifying components, distribution, etc.

– Greatly expanded standard service set Pragmatically, we are proceeding as follows

– Develop open source OGSA implementation> Globus Toolkit 3.0; supports Globus Toolkit 2.0 APIs

– Partnerships for service development

– Also expect commercial value-adds


Globus Toolkit Refactoring

Grid Security Infrastructure (GSI)– Used in Grid service network protocol bindings

Meta Directory Service 2 (MDS-2)– Native part of each Grid service:

> Discovery, Registry, RegistryManagement, Notification

Grid Resource Allocation & Mngt (GRAM)– Gatekeeper -> Factory for job mgr instances

GridFTP– Refactor control channel protocol

Other services refactored to used Grid services


Summary:Evolution of Grid Technologies

Initial exploration (1996-1999; Globus 1.0)– Extensive appln experiments; core protocols

Data Grids (1999-??; Globus 2.0+)– Large-scale data management and analysis

Open Grid Services Architecture (2001-??, Globus 3.0)– Integration w/ Web services, hosting environments,

resource virtualization

– Databases, higher-level services Radically scalable systems (2003-??)

– Sensors, wireless, ubiquitous computing


For More Information The Globus Project™

– www.globus.org Grid architecture

– www.globus.org/research/papers/anatomy.pdf

Open Grid Services Architecture (soon)– www.globus.org/research/

papers/ogsa.pdf

– www.globus.org/research/papers/gsspec.pdf

Grid Service Specificationand Demonstration

Steven Tuecke

Mathematics and Computer Science Division

Argonne National Laboratory


Use of Web Services (1)

A Grid service interface is a WSDL portType A Grid service definition is a WSDL extension

(serviceType) containing:– A set of one or more portTypes supported by

the service

– portType & serviceType compatibility statements, to support upgradability

> For discovery of compatible services when interfaces are upgraded

– Implementation version information


Use of Web Services (2)

A GSR is a WSDL document with extensions:– Extension to service element to reference

serviceType

– Service element extensions to carry the GSH, and the expiration time of the GSR

A GSH is an URL, with the following properties:– Globally unique for all time

– http get on GSH + “.wsdl” returns GSR

– Can derive GSH to Mapper from it Registry returns WS-Inspection documents

Documents

Globus Toolkit Futures: An Open Grid Services Architecture Ian Foster Carl Kesselman Jeffrey Nick Steven Tuecke Globus Tutorial, Argonne National Laboratory,