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, Ne. SC 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, Ne. SC Jan 06 © S. J. Coles 2006
The ECSES Demonstrator • e-Science pilot project • Proof of concept system • Numerous ‘hacks’! But… • Informed design for real service developed under Combe. Chem testbed project • J. Appl. Cryst. , (2005), 38, 819 -826 Usability WS, Ne. SC 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, Ne. SC Jan 06 © S. J. Coles 2006
Principal Components 1) 2) 3) 4) 5) 6) Application for an allocation Secure access to NCS Grid resources Sample submission Monitoring sample and queue status Data collection Raw data download Usability WS, Ne. SC Jan 06 © S. J. Coles 2006
NCS Grid Service (I) Usability WS, Ne. SC Jan 06 © S. J. Coles 2006
NCS Grid Service (II) Usability WS, Ne. SC Jan 06 © S. J. Coles 2006
Usability: Grid vs Web Services HTTPS Usability WS, Ne. SC 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, Ne. SC Jan 06 © S. J. Coles 2006
Security Signed certificate imported into browser Applicant identity independently verified by NCS CLIENT Panel award access to NCS RA KEYSTORE NCS RA signs key pair CSR NCS RA exports signed certificate NCS RA public key Usability WS, Ne. SC Jan 06 Passcode & signed PFX © 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, Ne. SC 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, Ne. SC 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, Ne. SC 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, Ne. SC 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 Usability WS, Ne. SC Jan 06 © S. J. Coles 2006
Скачать презентацию Experiences in deploying a useable Grid-enabled service for
e9f37df5acdc703f9c4cb6e3fdf30e8a.ppt