All HPC facilities, worldwide, provide software in a very different way to personal and corporate computing platforms. JCU HPC uses environment modules to deliver multiple versions of software to researchers using our multi-user HPC cluster. This approach is widely used for the following reasons:
- Most operating systems weren't written to deal with having multiple versions of the same software available. Even in cases where multiple versions are installed, e.g., java, it is left to a system administrator to set the version which everyone will use.
- Using environment modules, Individual users or groups can determine which version of software they wish to use.
- Loading of modules with version information maximizes your chance of being able reproduce your results upon demand.
- In the corporate world, system administrators have to configure a default version of piece of software (e.g., java) that everyone will use.
- Using environment modules also improves performance by reducing the length of your search path (executable of interest found sooner). It also reduces the chance of you having to deal with application name conflicts.
In 2021, HPC staff commenced a major project to replace all existing software (including conda environments) with containerized versions of the same software and/or environments. The container delivery platform being using is Apptainer (singularity) which mirrors the approach that all other HPC facilities are using or moving toward using. The move to containerized HPC is being driven by a requirement for all research to be done in a reproducible way.
For security reasons, all software installed as part of the OS must be kept up to date.
- This has potential to impact your computational research results.
- Most researchers would be unaware of the behind the scenes changes or what impacts they might have had.
- It would be nigh on impossible for me to recreate the state of HPC cluster operating systems at any nominated point in time.
Software installed using the traditional, compile from source, method comes with serious consequences to reproducible research.
- Such installs usually result in a software environment with a potentially very large number of unknown dependencies.
- Once again, this makes it nigh on impossible to reproduce at a later date.
Operating system and software providers release software with a defined lifecycle.
- When RedHat Enterprise Linux 6 (RHEL6) went end of life, we moved to RHEL7. All software had to be recompiled/reinstalled.
- Obtaining a copy of RHEL6 would be very difficult. Being given security clearance to use it would be even more difficult.
- After python 2 hit end of life a few environments that required python 2, indirectly, could not be reinstalled (dependency not available).
In many cases, the above points mostly relate to risk of work not being reproducible. Moving to containerized delivery of software provides a guarantee of reproducibility, assuming that the container platform continues to be available and supported.
Environment Modules Cheat Sheet.
You will need to replace any occurrence of
<software-name> and/or <version> below with an appropriate name/value.
Modification of your environment (paths & aliases)
To load the default version of a piece of software
The default version of a piece of software will usually be a safe (rather than latest) version.
To load a specific version of a piece of software
HPC staff recommend this approach as default versions may change with time.
To switch to another version of the same piece of software
To list changes that would be (or have been) made to your environment from loading a specific module
To unload a module you have loaded
Specification of a version shouldn't be required here.
To unload all of your currently loaded module
Information specific to JCU HPC configuration
Most module files, when loaded, will set an environment variable
<SOFTWARE>_HOME which holds the installation home for the software. For example, try
The most common environment variable modified by the loading of an environment variable is
PATH. This has been done for convenience.