Conference notes for 2021 11 09

Agenda for Lmod Meeting 2021-11-09 at 15:30 UTC (9:30 US Central)

• LMOD_QUARANTINE_VARS
• source_sh
• /etc/lmod/lmod_config.lua
• Depends_on fix for issue #531
• Maintainer for Lmod on debian systems: https://repology.org/project/lmod/versions
• Settarg will be discussed in the December Meeting

Attendees

• Robert McLay (TACC)
• Kenneth Hoste (HPC-UGent)
• Kurt Lust (HPC-UAntwerpen, LUMI User Support Team)
• Lev Gorenstein (Purdue)
• Raghu Reddy (NOAA/GDIT)

Overview of recent changes

• see https://github.com/TACC/Lmod/blob/master/README.new
• Lmod 8.5.23 is about to become Lmod 8.6.0 (after feedback)
• slides: https://github.com/TACC/Lmod/blob/master/my_docs/21/lmod_zoom_mtg_2021_11_09/presentation.pdf
• overview of new features on Lmod web page: https://lmod.readthedocs.io/en/latest/025_new.html

$LMOD_QUARANTINE_VARS

• Can be used to specify names of variables that can not be changed
  • Only works for regular environment variables, not for PATH-like variables
• Quarantined variables kicks in as soon as $LMOD_QUARANTINE_VARS is set (for example in .bashrc)
  • applies to any module load commands that are run afterwards

System-wide configuration file for Lmod

• Default location: /etc/lmod/lmod_config.lua (can be changed when configured Lmod build)
• Is evaluated during Lmod startup
• Priority: SitePackage.lua takes precedence over this (/etc/lmod/lmod_config.lua is loaded before SitePackage.lua)
• should be covered in the documentation once ReadTheDocs refreshes the docs @ https://lmod.readthedocs.io

source_sh

• re-implementation of Tmod 4.7 feature to support sourcing of shell scripts inside a module file using source_sh
• also covers aliases and shell functions that are defined by the script
• Lmod detects changes made to the environment, and stores that in the Lmod ModuleTable environment variables
• unloading a module that sourced a shell script works!
  • changes made by the script that was sourced are also reverted
• module show also works
• module refresh also works
  • can be used to ensure environment is correctly set up in new subshell
• relies on not having the script sourced already when loading the module
• Lev: tested, seems to work for basic scripts, but didn't work as expected for OpenFOAM or Spack init scripts...
  • Robert tested the Intel script, that does work
  • Lev will report the problems observed in a public forum (like Lmod mailing list)

LmodBreak

• new Lua function supported by Lmod 8.6, to support break that can be used in Tcl modules

$LMOD_SITE_MODULEPATH

• new in 8.5.18
• list of paths to prepend to $MODULEPATH before the first call to the Lmod command
• useful to deal with module reset that triggers reset to "system" $MODULEPATH
  • that is, the $MODULEPATH that's set when Lmod is run first (before any profile scripts are run)
• see also https://lmod.readthedocs.io/en/latest/030_installing.html#lmod-site-modulepath-label
• the logic for this is implemented in lmod/init
  • for example: https://github.com/TACC/Lmod/blob/28d8db5af58644fc48a9342ef4d1e1461e428deb/init/profile.in#L33

depends_on fix for issue #531

• see https://github.com/TACC/Lmod/issues/531
• warning is printed when a module that is registered as a dependency of a loaded module is no longer loaded
• this is included in Lmod 8.5.23

Wanted: maintainer for Lmod on Debian systems

• see https://repology.org/project/lmod/versions
• Aaron Zauner (azet) was doing this, but has switched tasks since
• last update is Lmod 6.6 for Debian/Ubuntu...
• Robert will ask the Lmod mailing list
• Kenneth can ping Aaron on Facebook for handover

Q&A

• Lev: automatically switching to a module tree that's specific to the type of compute node (CPU vs GPU)
  • via /etc/profile.d script
  • good question to ask Maxime @ ComputeCanada (via Lmod mailng list)

Next topics

• Settarg will be discussed in the December Meeting
• next meeting: Dec 7th at 15:30 UTC (first Tuesday of the month)