Ok, if you edit /lib/systemd/system/jupyter.service and change ExecStart to be as follows
ExecStart=/bin/bash --login -c 'conda activate fastai_dev;/opt/anaconda3/bin/jupyter lab --config=/home/jupyter/.jupyter/jupyter_notebook_config.py'
that will set the environment to the fastai_dev one that you created when you cloned the fastai_dev repo and installed the fastai2 package.
You need to run sudo systemctl daemon-reload and then restart the service with sudo systemctl restart jupyter to get the new file to be active.
Unfortunately, that didn’t solve my problem. If I do conda list torch in the notebook it says that pytorch version 1.3 is installed.
Here is sys.path:
['/home/jupyter/tutorials/fastai',
'/opt/anaconda3/lib/python37.zip',
'/opt/anaconda3/lib/python3.7',
'/opt/anaconda3/lib/python3.7/lib-dynload',
'',
'/opt/anaconda3/lib/python3.7/site-packages',
'/home/jupyter/tutorials/fastai/fastai_dev',
'/opt/anaconda3/lib/python3.7/site-packages/IPython/extensions',
'/home/jupyter/.ipython']