1. CernVM-FS Infrastructure for EGI VOs Catalin Condurache catalin.condurache@stfc.ac.uk - STFC RAL Tier1 EGI Webinar, 5 September 2013

2. CVMFS Infrastructure for EGI VOs What is CVMFS? CVMFS for User Communities CVMFS for NGIs CVMFS for System Administrators Conclusion References Q&A CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 2

3. What is CVMFS? Introduction History Benefits WLCG deployment Non-LHC use CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 3

4. What is CVMFS - Introduction CernVM-FS is a read-only file system widely used to access HEP experiment software and conditions data. Files and directories are hosted on standard web servers and mounted in the universal namespace: /cvmfs. File data and meta-data are downloaded on demand and locally cached. CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 4

5. What is CVMFS - History In last 3 years CernVM-FS has transformed distribution of HEP experiment software and conditions data in WLCG –Removes local install jobs –Removes heavily loaded file servers –Removes local software tagging process –Install once and you know the software is available at any sites with CernVM-FS Robust decentralized network of repository replicas CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 5

6. What is CVMFS - History By April 2014 main experiments will no longer run any local installation Number of cvmfs servers around world for other communities End 2012 RAL Tier 1 offered non-LHC Stratum 0 –About to be fully replicated at CERN –Also discussions with NIKHEF CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 6

7. What is CVMFS – WLCG Deployment Repositories hosted at CERN replicated to Stratum-1 replica servers in Europe, the U.S. and Asia A distributed hierarchy of proxy servers fetches content from the closest public mirror server CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 7

8. What is CVMFS – WLCG Deployment CVMFS clients connect to one of the Stratum 1 services (via local squid caches) Transparent fail-over to other Stratum 1 service in case of connection problems CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 8

9. What is CVMFS - Benefits Install once, run anywhere (with CernVM-FS client installed) Easily scalable with standard tools (squid caches) Often better performance –Reduced internal network traffic Can now re-export via NFS if it is impossible to install client on nodes (or little disk space) CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 9

10. What is CVMFS – Non-LHC Use Firmly established for WLCG Other communities? Easy to set up and run local CernVM-FS server –We know there are several – do not know where they all are Real benefit may come with network analogous to WLCG one CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 10

11. CVMFS for Non-LHC Use – Next Steps Who is interested in trying CernVM-FS? Do non-LHC, non-HEP VOs have different requirements? How best to build a resilient scalable network to support non-LHC (& non-HEP) VOs Who is interested in developing an international CernVM-FS infrastructure for other communities? CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 11

12. CVMFS for Non-LHC Use – What Will Be Needed Multiple Stratum-0s –VOs need to be able to install software (or upload tarballs) –Site needs to manage publishing repository on cvmfs- server –Do not require 100% uptime CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 12

13. A network (mesh) of Replicas – which provide the resilience –Pull data from Stratum 0s –Need to be resilient Server itself – with some TB storage Ideally pair of reverse proxy accelerators in front SLA similar to Tier 1s CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 13 CVMFS for Non-LHC Use – What Will Be Needed

14. (Regional) CVMFS proxy servers that fetch content from the closest public mirror server and serve the CVMFS clients –Trivial configuration –Minimal effort to maintain CVMFS client suite installed and configured on batch farms –The expertise already available at many sites –Experts ready to help new participating sites Enthusiasm! CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 14 CVMFS for Non-LHC Use – What Will Be Needed

15. CVMFS for User Communities Advantages Disadvantages Actions Ultimate Goal CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 15

16. CVMFS for User Communities - Advantages A single point where to upload and maintain the master copy of the software The rest is done by the replication mechanism – down to Stratum-1 mesh and beyond to the WNs cache via the squids No longer the need for multiple NFS mounts across the grid –If a VO has more than one point of presence (i.e. 1+ supporting sites) then 1+ NFS areas to maintain (already double the work needed) CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 16

17. CVMFS for User Communities - Advantages An unique definition for the VO_SW_DIR variable everywhere –i.e. /cvmfs/VO_repository_name Usually a single installation job to run at the site hosting the stratum-0 repository for that VO (for upload and maintenance) CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 17

18. CVMFS for User Communities - Advantages Possible alternative(s) –Web interface allowing tarball upload (and unpacking), also basic filesystems operations on /cvmfs/VO_repository_name –‘Power users’ given read-write access into /cvmfs/VO_repository_name –Other case scenarios to be discussed if need be CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 18

19. CVMFS for User Communities - Disadvantages Repositories are world-readable (CVMFS limitation) –Not a problem with LHC VOs though CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 19

20. CVMFS for User Communities – Actions VO Managers express interest and… …contact –CVMFS Task Force https://wiki.egi.eu/wiki/CVMFS_Task_Force please ask to be added to the mailing list –Appropriate NGI or Stratum-0 sites Along with RAL Tier1 other sites will act as (regional) CVMFS Stratum-0 soon (South Africa, Finland, Netherlands) CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 20

21. CVMFS for User Communities – Actions VO Managers identify cases where VOs are supported by both EGI and OSG –Make software distribution more homogeneous CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 21

22. CVMFS for User Communities – Ultimate Goal “We are making use of it already. Very nice and simple[…]” –excerpt from CVMFS Task Force wiki page What about having a lot of VO managers from various EGI VOs saying the same in 6-12 months time? CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 22

23. CVMFS for NGIs How can NGIs help? Ultimate goal CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 23

24. CVMFS for NGIs – How Can NGIs Help? Need to support CVMFS –understand sites availability to install clients –collect expression of interest from VOs CVMFS client suite needs to be installed and configured on WNs at sites Give support to emerging Stratum-0 sites if needed Assistance required to help the Stratum-1 network take shape CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 24

25. CVMFS for NGIs – How Can NGIs Help? Much more help required to deploy and maintain a hierarchy of proxy servers –Helpful to have access to squid farm service It could be 1-2 slots on the farm dedicated for squid farm service (if not already available) –And/or dedicated CVMFS squid nodes close to the batch farms optimal at least one such service per NGI ideally CVMFS squid service at each site CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 25

26. CVMFS for NGIs – How Can NGIs Help? CVMFS client suite needs to be installed and configured on WNs at sites Minimal changes otherwise –on existing squids just add the necessary CVMFS Stratum-1 endpoints CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 26

27. CVMFS for NGIs – Ultimate Goal Have CVMFS client suite installed by default on site batch farms! Have a CVMFS squid service per each NGI CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 27

28. CVMFS for Sys Admins How to convince them What is the real work needed Ultimate goal CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 28

29. CVMFS for Sys Admins – How to Convince Them No need any longer to maintain NFS areas to store the software at each batch farm Simple procedure to install and configure the CVMFS client at worker node level CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 29

30. CVMFS for Sys Admins – How to Convince Them Solutions available for diskless WNs or where CVMFS client cannot be installed –Use re-export feature of the latest client release Easy access to an active CVMFS community via mailing lists –Developers, sys admins involved in CVMFS for WLCG CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 30

31. CVMFS for Sys Admins – The Real Work Needed Install the latest CVMFS client production release across the entire farm –http://cernvm.cern.ch/portal/startcvmfs –client v2.1.X, documentation Modify VO_SW_DIR on WNs to point to CVMFS mount point (/cvmfs/VO_repository_name) CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 31

32. CVMFS for Sys Admins – The Real Work Needed Once configured for one VO, easy to replicate for further ones On existing squids just add the necessary CVMFS Stratum-1 endpoints Not complicated, but people might be reluctant CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 32

33. CVMFS for Sys Admins – Ultimate Goal Make CVMFS client suite part of the standard WN installation CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 33

34. Conclusion If you are –a VO willing to make use of CVMFS –a site willing to deploy CVMFS client –a site willing to run a stratum-0 repository –a site willing to run a stratum-1 replica then contact the CVMFS Task Force!! CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 34

35. References CVMFS Task Force wiki page –https://wiki.egi.eu/wiki/CVMFS_Task_Forcehttps://wiki.egi.eu/wiki/CVMFS_Task_Force CVMFS home page –http://cernvm.cern.ch/portal/filesystemhttp://cernvm.cern.ch/portal/filesystem RAL Tier1 CVMFS –https://www.gridpp.ac.uk/wiki/RAL_Tier1_CVMFShttps://www.gridpp.ac.uk/wiki/RAL_Tier1_CVMFS CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 35

36. Thank You! Time for questions and answers now… CVMFS Infrastructure for EGI VOs - EGI Webinar, 5 September 2013 36