# Environment modules on clusters

When working on a supercomputing cluster at, say, a university, it is important to have the right development or working environment. Without the correct software, computational research would grind to a halt.

Here I’ll discuss briefly what I’ve learned about a kind of configuration tool using environment modules. I checked my university’s cluster and it appears they do have it installed.

From my understanding, modules are a framework to easily change the shell environment. This appears to be a more general version of conda, which is primarily used to configure Python environments.

One example of modules being used is at the University of Pennsylvania, where you can get an idea of how to use it.

To see what kind of environments you have available, you can run the following.

$module avail ------------------- /usr/share/Modules/modulefiles -------------------- dot module-info null module-git modules use.own -------------------------- /etc/modulefiles --------------------------- mpi/openmpi-x86_64  Here we can notice two groups of modules that I have available. What’s nice is that it also shows where those module files are. For example, the null modules configuration file is this. #%Module1.0##################################################################### ## ## null modulefile ## ## modulefiles/null. Generated from null.in by configure. ## proc ModulesHelp { } { global version puts stderr "\tThis module does absolutely nothing." puts stderr "\tIt's meant simply as a place holder in your" puts stderr "\tdot file initialization." puts stderr "\n\tVersion$version\n"
}

module-whatis   "does absolutely nothing"

# for Tcl script use only
set     version      "3.2.10"


These modules seemed all cool and all. But then I was curious how I could use my own. Being on a shared resource, most people like me will lack the user permissions to modify root level files.

Luckily there is a way to load personal modules.

Say I copied the contents of the above module file to my home directory. I can then just point the module program to the file itself. Here I’ve also named the file null and put it into my home directory.

$module load ~/null  To see it was loaded, we can run the following. $ module list

This may be a convenient way to share environments across multiple users. This could help so that instead of each person having personal configurations, module configurations could point to some shared resources. This will not only free up storage on each individual’s partition, but also to keep everyone’s shell free of unnecessary environmental configurations and paths.