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Usability WS, NeSC Jan 06© S.J. Coles 2006
Experiences in deploying a useable Grid-enabled service for the National
Crystallography Service
Simon J. Coles
EPSRC National Crystallography Service
School of Chemistry
University of Southampton
Usability WS, NeSC Jan 06© S.J. Coles 2006
Requirements
• Remote user interaction with experiment
• Faster access to experimental data
• Robust security infrastructure
• Compatibility with NCS operational procedures
• Operational service (not demo!)
• Simple installation of client software
Usability WS, NeSC Jan 06© S.J. Coles 2006
The ECSES Demonstrator
SOAP/HTTPS/PGP
NCSGATEWAYSERVER
GASS GridData Service
X-Ray e - Laboratory
StructuresDatabase
ECSES Client
ComputationService
IT Innovation FIREWALL
SOAP/HTTPS/PGP
NC
S L
abo
rato
ry F
IRE
WA
LL
Globus 1.1.4 GRID
So
uth
amp
ton
Cam
pu
s F
IRE
WA
LL
UDP/TCP
X-Ray e-LaboratoryStructuresDatabase
Send samplematerial to
NCS service
Search materials databaseand predict properties using
Grid computations
Download fulldata on materials
of interest
Collaborate in e-Labexperiment andobtain structure
ComputationService
• e-Science pilot project
• Proof of concept system
• Numerous ‘hacks’! But…
• Informed design for real service developed under CombeChem testbed project
• J. Appl. Cryst., (2005), 38, 819-826
Usability WS, NeSC Jan 06© S.J. Coles 2006
Lessons from ECSES
• User authentication and security; single sign-on using Globus Security Infrastructure
• Use of Grid, as opposed to Web, Services; GS not flexible enough to interface to instrument
• Scheduling an experiment; timing between both parties
• Remote instrument control; degree of user control and interaction
• Communication between parties; video conferencing, audio multicasting & instant messaging
• Third party software; licensing and provision
Usability WS, NeSC Jan 06© S.J. Coles 2006
Principal Components
1) Application for an allocation
2) Secure access to NCS Grid resources
3) Sample submission
4) Monitoring sample and queue status
5) Data collection
6) Raw data download
Usability WS, NeSC Jan 06© S.J. Coles 2006
NCS Grid Service (I)
Usability WS, NeSC Jan 06© S.J. Coles 2006
NCS Grid Service (II)
Usability WS, NeSC Jan 06© S.J. Coles 2006
Usability: Grid vs Web Services
HTTPS
Usability WS, NeSC Jan 06© S.J. Coles 2006
Usability: Security
• WS approach and complexity of NCS operations necessitates design of a security infrastructure
• Risk assessment; Campus network, NCS computing, scientific instrument, data
• Level of access; User data, experiment control, management, administration
• Public Key Infrastructure; NCS certification practice, X.509 certificate issued by CA & RA
• Process-Based Access Security; Each NCS process validates user access according to defined requirements
• Sign-up process too complex for most NCS clients
Usability WS, NeSC Jan 06© S.J. Coles 2006
Security
NCS RA
KEYSTORE
Applicant identity independently
verified by NCS
Panel award access to NCS
CLIENT
CSR
NCS RA signs key pair
NCS RA public key
NCS RA exports signed certificate
Passcode & signed PFX
Signed certificate imported into browser
Usability WS, NeSC Jan 06© S.J. Coles 2006
Usability: Scheduling
• Timing sessions; instrument, video & audio• Sample scheduling embedded into Status
Service• Timing still difficult due to variable length of
experiments
• Video & audio problems; Session management (both client and provider), client software necessary, insufficient or irregular bandwidth
Usability WS, NeSC Jan 06© S.J. Coles 2006
Usability: Experiment Steering• Provider aspect
– Complete access to NCS systems and experiments undesirable
– Loose coupling of system to physical instrument necessitates both software and hardware systems to protect instrument
• Client aspect– Many NCS users are chemists using a service with no
knowledge or interest in the technique– Allocation on NCS relatively easy to acquire (relative
to other central facilities) – NCS is a data provision service, rather than the client
performing the experiment. Users prefer to delegate responsibility to expert staff at NCS
Usability WS, NeSC Jan 06© S.J. Coles 2006
Client Usability• Lightweight interface; access through standard web
browser• Simple electronic application and submission• Simple installation of certificate to meet security
requirements• Ability to easily view sample states
• Immediate availability of data on completion of experiment
• Difficulty in coinciding timing between provider and client
• Preference to delegate experiment work to service
Usability WS, NeSC Jan 06© S.J. Coles 2006
Service Provider Usability
• Significant move towards ‘paperless administration’ • Efficient (often automatic) management of user,
sample and experiment metadata/data• Less client queries• Simple reporting back to users through automated
email• User may access data themselves• Rapid reporting of usage statistics• Issuing certificates
• Install instrument safety hardware (and upgrade software safety) before full faith in remote control
Usability WS, NeSC Jan 06© S.J. Coles 2006
Current Situation
• Selected users at beta testing stage provided feedback which was included into release software
• System been in use at NCS for 6 months (without full client access)
• Certificates to be issued to all clients March 2006• Electronic application and submission to be fully
phased in (mandatory?) during 2006• Minor developments continually in progress• Feasibility study into transferability of software to
other chemistry services• Collaboration with larger central facilities on
remote instrument control / steering
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