Summary of GDB meeting (May 9, 2012)



  • Meeting organization
    • every meeting should have one or more minute takers
    • Meeting summaries: a TWiki area should be set up (WLCGGDBDocs)
    • someone in the room should monitor the chat area
  • Frederique: autumn remote meeting might be held in Annecy, will check
  • Main topics for next GDBs
    • June GDB: TEGs, post-EMI plans, RFC/SHA-2, gLExec, ...
    • July GDB: experiment reports, ... May change depending on final June agenda
    • Sep GDB: IPv6, ...
  • Actions to follow from previous meeting
    • perfSONAR tracking

TEGs: status and what next

  • big TEG meetings finished, just focused meetings on specific topics
  • WLCG workshop preceding CHEP:
    • priorities
    • open questions
    • unfinished areas
    • Initial proposal of working groups that WLCG should set up
    • Proposal for those general topics that could be dealt with in HEPiX
  • June pre-GDB:
    • DPM future
    • Conflict with LHCC week: some people not available

  • Claudio: glexec deployment desired at all CMS sites, with WLCG support
    • Ian B: could be a task for the requested WLCG operations support team
  • Jeremy: status of relocatable glexec?
    • Maarten: recipe provided, proven to work, but requires compilation per site; may make it easier in the future
  • Davide: WM TEG has many recommendations to be followed up

Experiment Resources in the Coming Years

General remarks from C-RSG

  • priorities should be set according to resource availability
  • pileup is an issue for 2012 data
  • ALICE: low CPU efficiency for chaotic analysis
  • keep requests reasonable for funding agencies

C-RSG main conclusions

  • Increase use of HLT farm in 2013 for reprocessing and simulation
  • Look at the possibility of using external sources for some particular activities, like MC
  • C-RSG would like to keep a balanced usage of different Tiers. Ensuring such a balance will maintain a healthy collaboration

Other actions

  • Collection of installed capacity data too complex: will do it manually using REBUS (some development needed first)
  • Need to progress with storage accounting

Experiments disappointed by the lack of interaction with C-RSG this year: probably the year with the least interaction

  • Used to be considered useful in the past
  • C-RSG made some recommendations not exactly appropriate or difficult to interpret
    • try separating organized and chaotic jobs for accounting? would require non-trivial developments in various places


  • Hans (Atlas):
    • grateful to sites
    • pileup much higher, different energy, not like 2011
    • 2013 extra requirements not a luxury, well justified
  • Helge: some criticism on the C-RSG can be defended, but various input data arrived rather late

LHCOPN/ONE Status and Future Directions


  • LHCOPN operations: it just works!
  • new T1s may come
  • dashboards, perfSONAR deployment improving, also for LHCONE


  • LHCONE operational and progressing
  • L3 VPN symmetric routing requirement
  • various project updates, e.g. GLORIAD, GEANT, NORDUnet, DANTE
  • L2 point-to-point service investigations


  • Michel: how to enforce perfSONAR everywhere on LHCONE? is it scalable?
    • John: most instances dormant for troubleshooting, some actively used for monitoring
  • Michel: how useful if mostly dormant? perfSONAR is used to establish baseline for further troubleshooting...
    • John: guidelines on TWiki, core testing sites decided per VRF (routing domain)
  • Michel: who is responsible for taking action on issues?
    • John: sites should set up alarms for themselves
  • Michel: site will contact NREN --> other NREN etc; same discussion as for OPN...

Federated Identity Management

  • remove identity management from services, allowing SSO
  • trust needed between service providers and identity providers, like with IGTF
  • communities also have attribute authorities, e.g. VOMS
  • examples: IGTF, educational (national, international), social networks (e.g. Google ID)
  • collaborative effort involves:
    • photon & neutron facilities
    • social science & humanities
    • high energy physics
    • climate science
    • life sciences
    • fusion energy
  • current summary document:
  • common requirements, some non-trivial
  • common vision statement
  • recommendations to research communities:
    • risk analysis
    • pilot project
  • recommendations to technology providers:
    • separate AuthN from AuthZ
    • revocation
    • attribute delegation to the communities
    • levels of assurance
  • recommendations to funding bodies:
    • funding model
    • governance structure
  • not only grid, also other collaborative tools (TWiki, Indico, mailing lists, ...)
  • pilot study foreseen at CERN, e.g. TWiki
  • how to involve IGTF?
  • MB endorsement needed (Ian B: next meeting)

  • Matteo: relation to cloud computing? input welcome for EGI work in that area
  • Dave: cloud implications have to be considered as well

KISTI, a new T1 for ALICE

  • T1 ascension procedure now officially documented
  • ramp-up milestones: candidate --> associate --> full T1
  • KISTI plan being prepared
  • Russian project: progress expected later this year

  • Michel: might extra resources in one place allow for a reduction elsewhere?
    • Ian B: normally not; ALICE in particular still have much less than their nominal requirements

HEPiX Prague Summary

  • very full program
  • new business continuity track
  • others: IT infrastructure, storage, grid/cloud virtualization, network & security, ...
  • energy efficiency: future meeting
  • fabric management changes
    • Puppet
    • Quattor
    • Nagios --> Icinga
  • batch:
    • PBS/Torque scalability issues
    • SLURM, Condor rising
    • xGE forum
  • clouds on the horizon of realism; OpenNebula, OpenStack
  • storage:
    • federation
    • what comes after RAID
  • Federated Identity Management
  • IPv6
  • Working Groups: virtualization, IPv6, storage, benchmarking
  • HEPiX very healthy!

WLCG Workshop

  • CHEP/LHC schedule mismatch for future workshops?
    • workshops can be standalone (again)
  • New York: TEG recommendations + exciting new developments
    • reserve a slot for glexec deployment timeline and hints
  • loose agenda to allow a lot of discussions
  • Gantt chart for Run-2 preparation?

  • Ian B: will send draft comments + questions to TEG chairs
    • Jamie: focus on explicit, time-bound recommendations
    • Ian B: do not repeat TEG discussions

HEPiX WG Report on trusted virtual images

Mandate almost fulfilled

  • image endorsement: approved JSPG policy
  • framework for publishing and distribution of images that can be integrated with any image repository implementation
    • integrated with StratusLab Marketplace
    • being integrated with OpenStack Glance
  • Technical arrangements have been defined for site contextualization and for exchange of information between site infrastructure and a running VM
    • E.g. remaining lifetime...
  • CERNVM images compliant and reviewed
  • experiment-specific images could directly connect to pilot framework
    • Probably the most desirable option

  • Dan: experiment should also be ascertained the image is what it expects, i.e. not replaced/updated by the site
    • This is by design!
  • Matteo: Glance vs. StratusLab?
    • Ulrich: site choice

WNoDeS: CNAF experience with virtualized WNs

  • WNoDeS in production since Nov 2009 at several Italian sites, incl. T1
  • included in EMI-2
  • mixed mode: use physical nodes as traditional batch workers and for VMs in parallel
    • some pros and cons
  • upcoming features: interactive, OCCI, web interface, dynamic private VLANs, federated access, storage
  • end of EMI timeline may have some impact

  • Matteo: mixed mode - jobs on hypervisor might spy on network traffic
    • Davide: an exploit would still be needed; already an issue without VMs today
  • Michel: usage by WLCG experiments?
    • Davide: high-memory VMs were deployed for ALICE; no use case yet for the others; some other VOs using special VMs, created by the site

Cloud Resources in EGI

  • resource providers and communities interested in clouds for various reasons
  • create community platform alongside grid infrastructure
    • interface to commercial providers
  • WGs to address technical issues and engagement; testbed
  • goals: blueprint, dissemination
  • standards and validation
  • resource typologies, heterogeneity, provider agnosticism
  • task force consisting of 23 institutions from 13 countries
    • stakeholders
    • technologies
  • federated testbed, living blueprint document
  • demo was given at EGI CF 2012
  • many consolidation activities next 6 months

  • Philippe: relation with HEPiX?
    • Michel: different areas
      • EGI: federated clouds
      • HEPiX: trust infrastructure for virtual images
    • Matteo: complementary; e.g. interested in Marketplace/Glance integration
  • Ulrich: EC2 support?
    • Matteo: yes, but most standard user interface is OCCI, not EC2
  • Michel:
    • HEPiX WG was started because of experiment wish for controlled (virtual) environment
    • sites: how can cloud-like resources be used transparently?
  • Jeff: Dutch communities have been asking for cloud resources, but not federated: why are federated resources needed?
    • Matteo:
      • we asked various communities and got different requirements
      • federated offer: user can handpick where to run jobs/VMs without knowing details of implementation; EGI can tailor
    • Michel: small communities may not ask for federated clouds, just resources with some implementation
  • Matteo: relation between private and public clouds; some communities already using Amazon because it is easier, less expensive

ATLAS viewpoint

  • various cloud integration and testing activities
  • Jeff: why?
  • Fernando:
    • some sites interested in cloud infrastructure
    • MC production in Amazon etc.
    • want to be ready for cloud resources
  • contextualization strategies
    • golden image expensive to maintain
    • HEPiX CDROM approach?
    • Puppet? how much can the image be changed?
  • image management issues: presently entirely manual, no signing of images

  • Tony: why/how does the image need to be contextualized by the VO?
  • Fernando:
    • install some packages + configuration files
      • not everything in CVMFS (e.g. Condor, Ganglia)
    • certificate handling
  • Dan: you need to give the image a secret to pull in jobs from Condor, typical workflow is:
    • we boot image running for a long time as a Condor worker; shut down when no work
    • credential needs to be passed and renewed --> handled by Condor
    • use of Condor also convenient for joining PanDA infrastructure
    • Condor also solves whole-node/multi-core problem
    • Ulrich: pass it as user data; got it to work with Puppet
  • Tony: site should have last word in contextualization for logging etc; put Condor in CVMFS!
  • Michel:
    • Contextualization initially designed to be done by site exclusively on an image built/tailored by the VO
    • Now VOs want to rely more on CVMFS to avoid too many images: issue with sustainability of image management without an image catalog
    • VO contextualization is a new use case, needs more thought but can probably be integrated in the model
  • Philippe: LHCb needs very little in CVMFS, e.g. mount point and script to set up environment
  • Ulrich: image needs to be bootstrapped with VO parameters passed as user data, image itself should not need to be touched
  • Philippe: indeed
  • Ulrich: potential issue with long-lived images, e.g. for SW updates
  • Tony: let the batch system shut them down as needed, see proposed mechanisms

LHCb viewpoint

  • not yet at the level of ATLAS; interested in CVMFS, lxcloud, commercial clouds (DIRAC extension)
  • consider cloud as yet another batch system? create overlays with pilots as usual
  • fair share mechanism vs. adding/removing VMs on demand
  • single-core VMs not OK
  • multi-cores: run N jobs in parallel, mix of CPU and I/O bound, or parallel Gaudi job
  • LHCb would like to couple virtualization and whole node scheduling
  • account VOs on wall-clock time, not CPU time


  • Accounting
    • Jeff: mismatch with cloud world; we need limits on wall-clock-HEPSPEC-hours!
    • Tony: wall-clock time accounting makes sense now
  • Jeff: ATLAS could take more when others are quiet and then run out of quota faster?
  • Michel:
    • it is an important question but this is not the right time for theoretical discussions on how scheduling will work in the cloud
    • need to get some small-scale workflows going to find and fix the issues in the whole chain
  • Dan: some effort available for projects with limited scope, e.g. using the HEPiX tools
  • Helge:
    • looking into different ways to set up cloud services, which should not concern experiments
    • also trying to get endorsed images to work
    • single- vs. multi-core is orthogonal
  • Dan: root access to VM image?
    • Ulrich: many/most sites cannot handle that, so all that is needed should be done beforehand or with trusted contextualization plugins
  • Dan: VM shutdown announcement needed for job cleanup
    • Ulrich: being looked into, some mechanisms already available
    • Jeff: imitate fuel gauge!
  • Michel: many ideas and questions to be further discussed in WGs etc.

-- MaartenLitmaath - 09-May-2012

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Topic revision: r8 - 2012-05-14 - JamieShiers
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