Hiding Packages and Modules

Sometimes it can make sense to create a module but then hide it from the list shown by module available. For instance, perhaps a module will only exist temporarily, needs to be tested by a large group but may have known limitations, or it uses a license that is only available to a limited segment of the user base.

The clusters have a postprocessing unit called hidelist that allows you to hide modules that match given search strings. There are currently two methods for specifying the modules to hide:

hide_list - list paths to modules relative to the module deployment root to hide if found
find_list - uses find to search for any file in the module tree that matches the given string, regardless of which directory or depth it occurs

Hide Mechanism

Lmod allows you to hide modules using a given hidden-modules file. The file uses a very simple format, with each module listed per line. For example, we hide the crayenv top-level modules using this file:

hide-modulefile /glade/u/apps/derecho/modules/environment/crayenv/22.12.lua
hide-modulefile /glade/u/apps/derecho/modules/environment/crayenv/25.03.lua
hide-modulefile /glade/u/apps/derecho/modules/environment/crayenv/23.09.lua
hide-modulefile /glade/u/apps/derecho/modules/environment/crayenv/24.03.lua
hide-modulefile /glade/u/apps/derecho/modules/environment/crayenv/23.12.lua
hide-modulefile /glade/u/apps/derecho/modules/environment/crayenv/23.03.lua
hide-modulefile /glade/u/apps/derecho/modules/environment/crayenv/23.02.lua

Unfortunately this file (as of March 2026) does not allow for operations such as globbing, so keeping these files up to date for older deployments can be challenging.

The hidden-modules file is specified to Lmod via the following environment variable set in ncarenv:

pushenv("LMOD_MODULERCFILE", "/glade/u/apps/derecho/25.10/envs/public/util/hidden-modules")

Tip

The pushenv method in Lmod is a way to override and environment variable only while the module is loaded. When the module is unloaded, any previously set value is restored. This can be quite handy over setenv, which leaves the variable unset when the module is unloaded, regardless of its previous value.

Build-env Only Packages

Occasionally, during testing, you will want to install a package into the build environment but for whatever reason you do not want it to end up in the public environment. You could hide the module, but another approach is to prevent it from being installed into public by the publish script. To do this, use the following configuration setting in packages.cfg to mark packages:

# DEBUG stack
mdep: compilers=nvhpc@25.9 mpis=cray-mpich@8.1.32 source=install publish=no
    parallel-netcdf@1.14.1 cppflags=-g
    netcdf+mpi+debug@4.9.3
    parallelio+logging@2.6.8 %TC% ^parallel-netcdf cppflags=-g ^netcdf-c +logging ^netcdf-fortran cppflags=-g
    esmf+mpi+debug@8.9.1 %TC% ^hdf5 %CMP% ^parallelio+logging ^parallel-netcdf cppflags=-g ^netcdf-c +logging ^netcdf-fortran cppflags=-g

In the example, all four debug packages are kept in the build environment only by specifying publish=no. If, later, you wanted to change this, you could remove publish=no from the section and run bin/install_packages again.