Python Virtual Environments

Python has built-in virtual environments, which contains a particular version of python with additional packages/modules that can be activated/deactivated at will. This guide will cover the basics on how to create an environment and install packages on it.

Create a New Virtual Environment

This should be done from an interactive session on a compute node.

To get an interactive session on a compute node, run the following:

srun --time=01:00:00 --nodes=1 --cpus-per-task=8 --partition=interactive --pty /usr/bin/bash

Set Up

To setup a python virtual environment, you will need to load your specific version of python. To find a list of available versions, you can run:

module spider python

Next, I would have to see if there are any prerequesite modules for python.

module spider <version-of-python-here>

For example:

module spider python/3.8.8-ucekvff

The output of this says that the python/3.8.8-ucekvff module requires gcc/10.2.0-zuvaafu . So we must load it first before we can load the python module.

For example:

module load gcc/10.2.0-zuvaafu
module load python/3.8.8-ucekvff

Before proceeding, ensure that you are in your /work directory and not your /home directory.

After running your module, create your virtual environment by typing in:

python -m venv <name-of-environment>

This will create a directory that contains the environment.

Activate the Environment

Activate the environment by running:

$ source <name-of-environment>/bin/activate

Your terminal will now look like this:

(<name-of-environment>) [user@bigram2 jones-lab]

Install packages

To search for certain packages, you can type in:

pip search <package-name>

If you wish to install a certain package, you can use:

pip install <package-name>

If you want a certain version of said package, you can give the package name followed by "==" with the version number:

pip install <package-name>==1.0.0

Deactivate the Environment

To get out of the environment simply type:


(This will not disconnect you from pronto/the node you are currently on)

Use a Virtual Environment in a Batch Job

# Load the python module. This should be the same version that was used to create the environment
module load gcc/10.2.0-zuvaafu
module load python/3.8.8-ucekvff
# Activate the environment as before. Replace /work/LAS/jones-lab/<name-of-environment> with the actual path to the environment.
source /work/LAS/jones-lab/<name-of-environment>/bin/activate
# Run your script. It will have access to all of the modules you installed in the environment.

More Information

If you plan on creating more environments, please ensure that you are creating them in /work instead of /home.

For more commands and further documentation, please visit: