I have set a few variable properties by going to the environment -> configuration -> Modify Software -> Environment properties.
When I SSH into the instance, activate the virtual environment and run python and check for the variable, it returns nothing.
This is what I type before I enter the python shell:
source /opt/python/run/venv/bin/activate
cd /opt/python/current/app/
python
>>> import os
>>> os.environ.get('VARIABLE')
>>>