Experiment Support

CERN IT Department

CH-1211 Geneva 23

Switzerlandwww.cern.ch/

it

DBES

WLCG Information Officer: the role and the challenges

F. Donno

CERN/IT-ES

ExperimentSupport Summary

• Who is the WLCG IO or who am I?

• What will I be doing?

• How would I interact with other involved parties?

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ExperimentSupport The WLCG Information System

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~1200 resource~ 374 site~100 top=1600 servers

Information Flow

Failure

?

??

InformationProviders

Static Dynamic

Consumer

ExperimentSupport Who am I

• Job description:

“Single point of contact for:– Improving the operational aspects of the service

• Deployment

– Ensuring coherence of the Information System infrastructure and its evolution (configuration, accuracy of information, migration planning, etc.)• Coherency and accuracy

– Collecting input from sites and users to facilitate an organized exchange with IS developers.” • Listen to customers

Please, send e-mail to Flavia.Donno@cern.ch

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ExperimentSupport What will I be doing?

• Listen to customers: the experiments– ALICE: WLCG IS not used. Interested in stable and

reliable CREAM-CE status info– ATLAS: “WLCG IS is a very low priority component”

• “We consider that fact that all information in the BDII has to be continually, actively published to be a serious design flaw of the system and it's fundamentally why we are unable to rely on it for ATLAS operations.”

– CMS: no official statement– LHCb: seem interested in information consolidation.

Consider splitting of dynamic and static information a priority.

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ExperimentSupport What will I be doing?

• Listen to customers: the experiments– Collected queries: semi-static information mostly needed– Support for fail-over and caching in services (ala FTS):

WMS– Proposal to improve stability of IS: OK! - See deployment– No Glue 2.0 in short-medium term plans.

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ExperimentSupport What will I be doing?

• Listen to customers: the sites– No explicit input yet– In general demand for easier deployment and information

feeding– Would like to avoid feeding resource information to

experiment specific data collectors

– Will launch a query on LCG-ROLLOUT– Involvement in top level BDII deployment proposal?– Following reported problems

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ExperimentSupport What will I be doing?

• Listen to customers: the developers– EMI services. To do: talk to project teams.– Storage Info providers, software subsystem, CE voview.

Who is responsible?– What else outside EMI scope ?– Define what is really needed– Can some of the subsystems disappear?

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ExperimentSupport What will I be doing?

• Listen to customers: other consumers– Monitoring/accounting tools, gstat, management– Accuracy of published information– On-going definition of essential objects

• Did we miss anybody?

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ExperimentSupport

D R A F T P R O P O S A L

• Focus on– Compilation of a WLCG usage profile

• A first draft approved by the experiments to be ready by end of January 2011

• This will be taken as reference for information consolidation and prioritization of activities

• Risks : – not fully descriptive – Please help!– frequent reviews needed.

– Working group on evolution of WLCG IS?– Continuing investigations

Some planning

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Listen to customers

ExperimentSupport Deployment

• Proposal presented at the MB on September 28, 2010:

“Deployment Strategy for Top-Level BDII”– Query Load

• High CPU capacity (150MB info)

– Network Latency• It affects query response time and reliability• Query “close” instance

– Support• Critical service: monitoring, reliable hardware setup• Releases must be carefully followed.

At least 2 Top Level BDII instances per continent: – Triumf and BNL or FNAL– CERN, RAL, KIT, PIC, CNAF, NIKHEF– Taiwan and KEK or Tokyo

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ExperimentSupport

D R A F T P R O P O S A L

• Focus on– Top level BDII deployment strategy

• To be defined and discussed with all involved parties (EGI, OSG, T1s)

• Failover strategy based on basic network topology/performance?• First detailed draft by February 2011 ?

– Participation in OSG working group to define requirements for an OSG Top level BDII.• Report available. • Presented/discussed on November 9, 2010 at FNAL.

Some planning

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Deployment

ExperimentSupport

D R A F T P R O P O S A L

• Focus on– Information cleaning

• Removal of deprecated GlueLocation object replicated per tag published by the subcluster – responsible for BDII pollution!

– GGUS ticket # 63478

– Storage Information Providers accuracy– Looking into gstat– Focusing on Tier-2 resources– Developing parsing tools (to be fed into gstat)

– Installed Capacity– Share– CPU scaling factors

Some planning

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Coherency and accuracy

ExperimentSupport

How would I interact with other involved parties?

• Experiments– Identification of IS related people

• Sent e-mails to individuals; personal discussions• Mailing list?

– Statement on WLCG IS usage

• Developers• Within EMI : need to establish an official communication

channel? What can WLCG ask? How can the original plans be modified? What is the expected response time?

• Other subsystems not part of EMI. Need explicit WLCG commitment.

– Storage Information providers (castor, xroot, bestman)– lcg-info-dynamic-scheduler – Installed software publishing

• Use GGUS SU

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ExperimentSupport

How would I interact with other involved parties?

• Sites– Use LCG-Rollout– Subscribed to GGUS relevant SUs– Direct contacts in case of problems– Spread the news that the WLCG IO is there ;-)

• Other Consumers– Mainly GGUS, e-mail exchange with individuals– Report to WLCG MB/GB for further input?

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ExperimentSupport

How would I interact with other involved parties?

• Operations• EGI: Initial discussions with Chief Operations Officer (T. Ferrari).

Need to establish communication channels and procedures• OSG : Working group established. Communications channels to

be defined.• NDGF: Contacts with the NDGF’s contact for the CERN

experiments (O. Smirnova). Established channel for important annoucements.

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ExperimentSupport Conclusions

• WLCG Information System– Not simply a BDII

• WLCG Information Officer– Contact person to help improve reliability of the service and

information provided– Interacting with experiments, sites, EMI, EGI, OSG, NDGF, WLCG

management

• First planning– Use case collection– Top Level BDII deployment strategy– Information consolidation and cleaning

• Initial communication channels established• Questions? Send e-mail to Flavia.Donno@cern.ch

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