This information is for a release that is no longer supported by the Globus Toolkit. The currently supported versions of the Globus Toolkit are 4.2 (recommended) and 4.0.
Status and Plans for Globus ToolkitTM 3.0
July 22, 2003
As part of an ongoing effort to improve the functionality of the Globus Toolkit*, the Globus Project launched an R&D program in 2001 aimed at creating a next- generation Globus Toolkit 3.0 (GT3) based on Open Grid Service Architecture (OGSA) mechanisms. In this fact sheet, we describe the implications of this evolution for current Globus Toolkit 2 (GT2) users and the current status and future plans for GT3. Because these plans will continue to evolve, interested users should periodically check http://www.globus.org/toolkit/ for updates. Please send feedback to info@globus.org. A companion document, the "GT3 FAQ", contains considerably more detail on many of the points mentioned here. The GT3 FAQ is available at http://www.globus.org/toolkit/faq.html.
Topics Covered in this Fact Sheet
- Important Things to Know about GT3
- Globus Toolkit--Now and in the Future
- GT3 Release Contents
- Terminology
Important Things to Know about GT3
The intent behind GT3 is to deliver an open source implementation of OGSI, several OGSI-compliant services corresponding to familiar GT2 services, and the ability to create new OGSI-compliant services.GT3 provides the same set of major features as those found in GT2. Specifically, it includes software that provides Grid security (GSI), remote job submission and control (GRAM), high-performance secure data transfer (GridFTP), and consistent interfaces to system and service information (MDS).
All of the components provided by the GT2 for building Grid infrastructures and for developing Grid applications remain available in GT3. The GT3 FAQ contains details about the operational environments supported by GT3 services.While the key services provided by GT3 are now presented via OGSI-compliant interfaces, and while these OGSI-compliant interfaces are implemented in Java, many services still have high-performance (and familiar) back-end implementations written in C. Existing GT2 configuration features (job manager interfaces, MDS information providers) are still supported. In some cases, OGSA makes these even easier to use. The GT3 FAQ explains more about how this applies to each GT3 service.
The most important advantage of basing GT3 on OGSA is that it both leverages and provides additional support to industry standardization around Grid protocols, both in e-Business and in e-Science.OGSA's most striking technical contributions to the Globus Toolkit are in the area of extensibility and manageability.
Previous versions of the Globus Toolkit came with a set of predefined services (GRAM, GRIS, GIIS, GridFTP). These services were largely independent of each other and had few common features (the notable exception being the Grid Security Infrastructure), so investments in developing, using, or managing one service made little or no contributions to developing, using, or managing other services. The OGSA architecture and OGSI infrastructure provide a common framework for Grid services, so developing new OGSI-compliant services (or specialized versions of existing services) is quite straightforward. Every OGSI- compliant service can be used and managed via common interfaces, so building systems and applications with OGSI-compliant services is much easier. The GT3 FAQ includes details on how to get started learning about Grid service development and how to contribute new Grid services to the Grid community or to the Globus Toolkit.
Globus Toolkit--Now and in the Future
While GT3 (released on 30 June 2003) is the current production version of the Globus Toolkit, we recognize that there is a large user community that has made major investments in the Globus Toolkit 2 code base. This community quite reasonably expects to see continued support and a reasonable migration path to GT3. We are committed to supporting this community as follows:
- GT2 Support: The GT3 distribution includes a full set of components based on the GT 2.4 distribution. Though the GT2 components will be deprecated over time, support for individual components will continue based on community needs (subject as always to available resources.)
- Migration: GT3 supports GRAM and GridFTP client API-level compatibility with GT2, thus allowing GT2 code to run with GT3 after relinking. In addition, GT2 and GT3 installations will be able to run simultaneously on the same resource (with limited interoperability), thus facilitating transition. We welcome suggestions for other ways of assisting with migration.
- Security Infrastructure: GT3 will, like GT2, make use of X.509 certificates, thus preserving the community's investment in certificate authority rollouts for authentication.
GT3 Release Contents
| GT3 OGSI and Related Features | |
| OGSI Reference Implementation | A stable implementation of the Grid Service Specification in Java |
| OGSA Security | SOAP message security based on GSI |
| Java SDK | APIs and tools to simplify the development of OGSI-Compliant services and clients |
| Samples, documentation and demonstrations | |
| Runtime | Four
Java hosting environments
|
| Command line and GUI clients to facilitate testing of OGSI-Compliant Services. | |
| GT3 Grid Services | |
| Services | OGSI-Compliant database services contributed by the UK eScience Program. (Implemented in Java.) |
| OGSI-Compliant GRAM service, including resource-information-discovery protocols (notify/subscribe). (The GRAM Service is implemented as a Java wrapper around existing C code.) | |
| GT3-Security-Compatible GridFTP service. It will offer the same interfaces and protocol as the GT2 implementation, and will interoperate with GT2 GridFTP clients. (Implemented in C.) | |
| OGSI-Compliant MDS Index Service (aka GIIS), supporting aggregation of information from other services and information providers that provide host information. (Implemented in Java.) | |
| An OGSI-Compliant prototype Reliable File Transfer (RFT) service. | |
| A GT3-Security-Compatible Replica Location Service (RLS). | |
| Client APIs | APIs providing WSDL-based Java bindings for all OGSI-Compliant Grid Services |
| GT2-compatible GRAM client APIs implemented in terms of hand-coded C proxies. This will let current users of the C GRAM APIs run existing applications against OGSI-Compliant GRAM services. | |
| GT3-Security-Compatible GridFTP client. This is the GT2 GridFTP protocol enhanced to support GT3 Security. (Implemented in C.) | |
| Tools | Samples, documentation and demonstrations of GT3 Grid services |
| GT3-Security-Compatible GridFTP GT2 client tools. | |
| GT2 Components | A full set of GT2 components based on the GT 2.4 distribution |
Terminology
OGSA refers to the Open Grid Services Architecture described in The Physiology of the Grid: An Open Grid Services Architecture for Distributed Systems Integration by Foster, Kesselman, Nick, and Tuecke (http://www.globus.org/alliance/publications/papers.php#OGSA). OGSA addresses architectural issues related to broadly interoperable Grid services.
OGSI refers to the Open Grid Services Infrastructure, based on the Grid Service Specification (http://www-unix.globus.org/toolkit/draft-ggf-ogsi-gridservice-33_2003-06-27.pdf). The GSSpec specifies the way in which a client interacts with a Grid service. OGSI software provides mandatory Grid service features, such as service invocation, lifetime management, a service data interface, and security interfaces that ensure a fundamental level of interoperability among all Grid services.
GT3-Security-Compatible refers to a client or a service that understands the GT3 GSI proxy certificates. GT3-Security-Compatibility does not imply OGSI-Compliance. OGSI-Compliant Service refers to a service that is built using and conformant to the Grid Service Specification; the protocol of an OGSI-compliant service is described by WSDL. OGSI-Compliant Services are GT3-Security-Compatible.
OGSI-Compliant Client refers to a client sending messages that are compliant to the WSDL definitions defined in the Grid Service Specification. This is typically done using a client proxy that is generated from the Service's WSDL. The client can be implemented in any language that understands the WSDL bindings exposed by the OGSI-Compliant Grid Service. If a client is OGSI-Compliant, GT3-Security- Compatibility is implied.
* And also in response to detailed, although in the aggregate contradictory, feedback from our user community, which might be summarized as: "nothing should change but everything must evolve!"