WLCG DOMA BDT Meeting

Wednesday 2 Mar 2022, 16:30 → 17:30 Europe/Zurich

Brian Paul Bockelman (University of Wisconsin Madison (US)), Maria Arsuaga Rios (CERN), Petr Vokac (Czech Technical University in Prague (CZ))

Topic: WLCG DOMA BDT Meeting

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1 Hot topics

Starting with next (16 March 2022) WLCG DOMA BDT meeting we are going to use different Zoom room (integrated with CERN Indico).

SRM/HTTP Update (Petr)

• CMS has moved its FTS to enable WebDAV + SRM/HTTPS (n.b. - in time for the tape exercise!)
• FTS team is considering to enable this by default as there are few experiments who need this disabled.
• Any issues arising?
  • Issues with DAVIX writing a temporary file on FTS server.  Probably FTS streaming issues.  Suggest FNAL ensures streaming is disabled.

 

2 Packet marking

Speakers: Marian Babik (CERN), Shawn Mc Kee (University of Michigan (US))

BDT_ Scitags_ Packet and Flow Marking .pdf

• Packet marking is part of the "SciTags" activity in the Research Network Technical WG.  95 members from 50 orgs.
• Primary goal: allow tracking and correlation of transfers with R&E network provider's network flow monitoring.
  • Can associated flows with a specific experiment or activity.
  • Provides sites with more visibility into network flows.
• How tags works:
  • Packet marking: markers are added to each packet.
  • Flow marking: UDP firefly sent out periodically, associated with the flow.
  • Network-level collectors at the respective entities collect fireflies or examine packets; hook into the respective analytic platforms.
  • See: https://www.scitags.org/api.json
• WLCG:
  • Experiment-level systems have knowledge, pass it to FTS3.
• Status:
  • Flow marking works with IPv6 and IPv4, hence is the focus.
  • XRootD 5.4.0 supports UDP fireflies.
    • N.b. - XRootD docs: https://xrootd.slac.stanford.edu/doc/dev54/xrd_config.htm#_Toc88514010
  • External-to-storage script based on netstat information.
  • ESNet and Jisc/Janet have deployed collectors.
  • Simplified deployment was done during the last data challenge.  Able to correlate UDP fireflies with netflow data.
• Various additional links to the project on the slides.
• Discussion:
  • Does the prototype work with HTTP?  A: Yes (Brian thinks it might not work with HTTP push)
  • Technical discussion - note that the fireflies are only sent at beginning and end?
  • Timeline?  DC2023.
  • Who is onboard?
    • ATLAS is enthusiastic, others are backing / provide interest.
  • What about dCache?
    • Currently used the netstat version.
    • dCache team is aware of the activity but not clear if there's a timeline yet.  ACTION ITEM: Need to get input from Tigran.
  • How are flows marked precisely?  E.g., HTTP headers?  TBD.

 

3 Token Authorization testbed

Speaker: Francesco Giacomini (INFN CNAF)

token-compliance-tests_20220302.pdf

• See attached slides.
• Current testbed gets nightly and also Jenkins integration
• Walked through last night's results.
• Open issues:
  • Assumes use of issuer implies group membership.  Decision: must be explicit
  • Group vs Scopes.  Decision: both.
• XRootD failures:
  • There are some open items, mostly around the HTTP status codes.
  • ACTION ITEM: Organize a discussion with Francesco, Brian, Elvin (maybe, TBC), and someone from RAL.  James Walder.

4 Tape REST access

Speaker: Cedric Caffy (CERN)

DOMA BDT MEETING 2nd of March - Tape REST API current status.pdf

• Last Friday, finished the discussions of the REST API.
• Not switching to doing the REST API reference doc to capture the agreed approach "on paper".
• CERN CTA prototype is working to implement the final draft.

5 AOB

• CMS reconfigured to TAPE transfers to SRM+HTTPS
• CERN FTS3 public instance will be reconfigured to also prefer HTTPS for as SRM TURL protocol (RQF1986690)

 

 

Tokens and testing (Maria):

• Can we retire the HTTP-TPC nightly email?  Effectively already done due to technical issues but we can probably just retire this as HTTP-TPC is in production.
  • https://github.com/paulmillar/http-tpc-utils
• Should we commission a XRootD protocol testbed?  Probably too early - need more agreement on the approach.
  • Recap of discussion on XRootD ZTN GitHub issue: https://github.com/xrootd/xrootd/issues/1584