Conference notes for 2022 11 08

Agenda for Lmod Zoom Mtg Nov. 08, 2022

• Q/A
• Discussion on module category
  • see https://github.com/TACC/Lmod/pull/600
  • to what extend can output be controlled from a hook?
    • Lmod has two types of tables:
      • beautiful tables
        • these "go horizontally"
      • column tables (as produced by "ml cat" or "ml" or "ml av")
    • Alan is looking into support for subcategories in hook
      • mostly working, but can't (always?) control order of how subcategories appear in output
• Renaming master branch to main
• The sourceforge Git repo has been removed
  • Now only contains a README file that points to GitHub repo
  • Due to problems with mirroring between SourceForge + GitHub
  • Tarball distribution will continue
• File and Internal changes (to get rid of "master" term in the codebase)
  • Also helps with tab completion in editor (Master vs MasterControl)
  • Changing MasterControl.lua -> MainControl.lua
  • Changing Master.lua -> Hub.lua
  • Internal Change masterTbl() -> optionTbl()
  • Note: masterTbl = optionTbl so that the files SitePackage.lua and /etc/lmod/lmod_config.lua can continue to use masterTbl() to access commandline options. This means that Sites do not have to change to optionTbl().
    • Can't produce a (deprecation) warning when masterTbl is still used since that would be visible to end users of Lmod
• Should users be allowed to unload dependent modules?
  • see thread on Lmod-users mailing list: https://sourceforge.net/p/lmod/mailman/message/37730407
  • triggered by integrating Lmod into JupyterHub
    • users can load modules through clicking
    • unloading of modules can easily be done accidentally in this context
    • fixing that mistake again is tricky...
  • with depends_on, Lmod actually knows when a required module gets unloaded (since it prints a warning)
    • but there's currently no option to make this an error
  • could be supported through a new "requires" statement, which could be stricter than "depends_on"
    • "requires(Python)" would not allow unloading Python unless Jupyter is unloaded
  • another option could be to have to add a configure option to Lmod to make "depends_on" more strict
    • something like LMOD_DEPENDS_ON_UNLOAD=warning vs LMOD_DEPENDS_ON_UNLOAD=error (or 'strict'?)
  • things get complex with depends_on in a hierarchy
  • with depends_on: if gnuplot is loaded directly by the user, it's not considered a dependency by Lmod
    • so unloading Octave (which depends on gnuplot) would not trigger an unload of gnuplot
  • Lmod could perhaps also support automatically unloading of modules that depend on what's being unloaded
    • for example unload TensorFlow if Python gets unloaded
• Presentation "How Lmod processes TCL modulefiles"
  • slides at https://github.com/TACC/Lmod/blob/main/my_docs/22/lmod_zoom_mtg_2022_11_08/presentation.pdf

Attendees

• Robert McLay (TACC)
• Kenneth Hoste (HPC-UGent, Belgium)
• Alex Domingo (Vrije Universiteit Brussel, Belgium)
• Danilo González (HPCNow!)
• Dan Green (NC State Univ.)
• Alan O'Cais (CECAM/University of Barcelona)
• Raj Ayyampalayam (University of Georgia)
• Google Pixel 6a (?)
• mk (?)
• Matthew Cawood (TACC)

Next meeting

• Tue 6 Dec 2022 at 09:30 US Central / 15:30 UTC