Experience with dynamic resource provisioning of the CMS online cluster using a cloud overlay

Journal Article · Tue Sep 17 00:00:00 EDT 2019 · EPJ Web of Conferences

DOI:https://doi.org/10.1051/epjconf/201921407017· OSTI ID:1574987

Andre, Jean-Marc ^[1]; Behrens, Ulf ^[2]; Branson, James ^[3]; Brummer, Philipp ^[4]; Chaze, Olivier ^[5]; Cittolin, Sergio ^[3]; da Silva Gomes, Diego ^[5]; Darlea, Georgiana-Lavinia ^[6]; Deldicque, Christian ^[5]; Demiragli, Zeynep ^[6]; Dobson, Marc ^[5]; Doualot, Nicolas ^[1]; Erhan, Samim ^[7]; Richard Fulcher, Jonathan ^[5]; Gigi, Dominique ^[5]; Gladki, Maciej ^[5]; Glege, Frank ^[5]; Gomez-Ceballos, Guillelmo ^[6]; Hegeman, Jeroen ^[5]; Holzner, Andre ^[3] ; Lettrich, Michael ^[5]; Mecionis, Audrius ^[8]; Meijers, Frans ^[5]; Meschi, Emilio ^[5]; K.Mommsen, Remigius ^[5]; Morovic, Srecko ^[1]; O’Dell, Vivian ^[1]; Orsini, Luciano ^[5]; Papakrivopoulos, Ioannis ^[9]; Paus, Christoph ^[6]; Petrucci, Andrea ^[10]; Pieri, Marco ^[3]; Rabady, Dinyar ^[5]; Racz, Attila ^[5]; Rapsevicius, Valdas ^[8]; Reis, Thomas ^[5]; Sakulin, Hannes ^[5]; Schwick, Christoph ^[5]; Simeleviciu, Dainius ^[11]; Stankevicius, Mantas ^[8]; Vazquez Velez, Cristina ^[5]; Wernet, Christian ^[5]; Zejdl, Petr ^[12]

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1. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
3. Univ. of California, San Diego, CA (United States)
4. European Organization for Nuclear Research (CERN), Geneva (Switzerland); Karlsruhe Inst. of Technology (KIT), Karlsruhe (Germany)
5. European Organization for Nuclear Research (CERN), Geneva (Switzerland)
6. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
7. Univ. of California, Los Angeles, CA (United States)
8. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Vilnius Univ., Vilnius (Lithuania)
9. National Technical Univ. of Athens, Athens (Greece)
10. Rice Univ., Houston, TX (United States)
11. European Organization for Nuclear Research (CERN), Geneva (Switzerland); Vilnius Univ., Vilnius (Lithuania)
12. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); European Organization for Nuclear Research (CERN), Geneva (Switzerland)

The primary goal of the online cluster of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) is to build event data from the detector and to select interesting collisions in the High Level Trigger (HLT) farm for offline storage. With more than 1500 nodes and a capacity of about 850 kHEPSpecInt06, the HLT machines represent similar computing capacity of all the CMS Tier1 Grid sites together. Moreover, it is currently connected to the CERN IT datacenter via a dedicated 160 Gbps network connection and hence can access the remote EOS based storage with a high bandwidth. In the last few years, a cloud overlay based on OpenStack has been commissioned to use these resources for the WLCG when they are not needed for data taking. This online cloud facility was designed for parasitic use of the HLT, which must never interfere with its primary function as part of the DAQ system. It also allows to abstract from the different types of machines and their underlying segmented networks. During the LHC technical stop periods, the HLT cloud is set to its static mode of operation where it acts like other grid facilities. The online cloud was also extended to make dynamic use of resources during periods between LHC fills. These periods are a-priori unscheduled and of undetermined length, typically of several hours, once or more a day. For that, it dynamically follows LHC beam states and hibernates Virtual Machines (VM) accordingly. Finally, this work presents the design and implementation of a mechanism to dynamically ramp up VMs when the DAQ load on the HLT reduces towards the end of the fill.

• Research Organization: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: AC02-07CH11359
• OSTI ID: 1574987
• Report Number(s): FERMILAB-CONF-19-549-CMS; CMS-CR-2018-398; oai:inspirehep.net:1761581; TRN: US2001157
• Journal Information: EPJ Web of Conferences, Vol. 214; ISSN 2100-014X
• Publisher: EDP Sciences
• Country of Publication: United States
• Language: English

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97 MATHEMATICS AND COMPUTING