GridFE: Web-accessibleGrid System Front End

Jared Yanovich, PSC

Robert Budden, PSC

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Preface

• User adoption of grids remains limited by obstacles in usability– Ease of access and use of a grid are essential– Bad initial user experiences are hard to overcome

• Web-based front ends can ease user access to a grid, including facilities to:– Simplify user authentication and credential

management– Guide users in gathering job submission parameters

and submitting jobs– Monitor jobs submitted and gather output

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SuperComputing Science Consortium

• SuperComputingScience Consortium– Regional partnership

• National Energy Technology Laboratory• Pittsburgh Supercomputing Center• West Virginia University• Carnegie Mellon University• University of Pittsburgh• WV Governor's Office of Technology• Institute for Scientific Research• Duquesne University• Waynesburg College• NASA IV & V :

– Objective: enhance access to computational resources to advance scientific research

– http://www.sc-2.psc.edu/

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(SC)2 SABER Grid

• Common grid infrastructure between computational resources at DOE NETL, PSC, and WVU– Commodity Intel IA32 clusters / Linux

• Accessible by researchers, faculty and students at (SC)2 member sites

• Used for research computing and computer science coursework

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GridFE

• Designed to be easy to use• Developed for use with Globus

– Globus is very common– Many APIs for accessing– Globus protocols exist and are readily

available

• Features supported by GridFE: logging in/authentication, job submission, job output retrieval

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Logging In

• HTTP authentication over SSL is used to log in• Messy details of certificates all handled on behalf of user

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Logging In (2)

• For SABER, accounts are managed through Kerberos• To authenticate on the command line, the user must run:

– kinit– kx509– kxlist

• GridFE handles this on behalf of the user

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Logging In With mod_fum

• HTTP authentication handled by mod_fum, an Apache module written to leverage KX509 to generate grid proxy certificates

Apache Web BrowserClient

mod_fum

KerberosDomain

Controller

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mod_fum (2)

• After successful Kerberos authentication via libkrb5, mod_fum generates a KX509 certificate from the Kerberos ticket using libkx509 from the KCA/KX509 project

• A short-lived X.509 certificate is generated by the KCA corresponding to the KX509 certificate via libkx509

• The X.509 certificate is later used to authenticate to the grid

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Portal Interface• Hyperlinks to

common grid functionality:

• Submit jobs

• Previously submitted jobs’ status

• SABER news

• Proxy certificate information

• Grid node availability

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Job Submission

• HTML form controls for all job submission parameters

• Job identification

• Executable path

• Target host

• Files involved

• Equivalent to command

line invocation of

globus-job-submit

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Job RSL

• Resource specification language (RSL) describes job

• Used by job submission manager and is needed to submit jobs

• It also allows:– Job quantization – specify all resources associated

with the job– Useful for re-running same job

• GridFE constructs RSL for jobs on behalf of the user, additionally providing optional access to it

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Job Status

• Job status page lists previously submitted jobs and their status

• Comparable to executing globus-job-status for each job submitted

• Follow a job to retrieve output

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Job Output

• Job output page shows any output the job generated

• Easy to download and save

• Equivalent to invoking the globus-job-get-output command line utility

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GridFE Backend Architecture

ApacheTomcat

(Java ServletRunner)

JavaInterpreter

GridFEServletModules

CoG Libraries

Web Client

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Phew!

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System Design

• Authentication handled by custom Apache module mod_fum• Grid functionality divided into Web pages• Web pages generated by Java servlet• Grid Commodity Toolkit (CoG) used by GridFE Java servlet to participate in grid protocols

CoG

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GridFE Java Servlet Class Hierarchy

GridFE Page

OOF – Generic objectoutput formatting

JASP – Java Web applicationservice routine package

gridfe – grid- andWeb page-related

Page Header

Paragraph

Forms

Table

Submit job

Retrieve job output

Node availability

MiscellaenousRoutines for

Web applications

GridJob

Certificate

RSLelement

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Related Work

• Other portals provide Web-based access to grid systems: OGCE, and GPDK

• However, they are not tailored for a Kerberos authentication environment

• Also, GridFE consists of a simpler interface providing only essential grid functionality, lowering the learning curve to grid adoption

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Conclusion

• Grid systems are an important computational resource

• It is essential that grid systems be accessible and easy to use

• GridFE was designed to reduce obstacles to allow users to harness the power of grid systems– Easy-to-use interface– Authentication and credential management simplified– Tools to assemble job descriptions, submit and

monitor jobs, and gather output– Instructional components to help users learn about

and use grid middleware

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Future

• New features planned:– Enhanced job submission controls– Replica Location Service support

• Long-term support planned:– Grid information/service browsing– Enhanced data transfer support– Grid workflow management

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Further Information

• “GridFE: A Web-accessible Front End to a Grid System”, R. Budden et al., PSC, Oct 2005, http://www.psc.edu/~yanovich/gridfe.pdf

• KCA/KX.509 Project, http://www.citi.umich.edu/projects/kerb_pki/

• Apache Web Server Project, http://www.apache.org/

• Globus Alliance, http://www.globus.org/• Grid Commodity Toolkit, http://www.cogkit.com/