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