= How to use GPUs on NLP Centre servers =

The following servers have GPUs:
* apollo
* ephimetheusX



1. find available GPUs: run `gpustat` or `nvidia-smi`
2. `export CUDA_DEVICE_ORDER=PCI_BUS_ID`
3. choose a GPU with no running processes
4. limit your process to only selected GPU:
   `export CUDA_VISIBLE_DEVICES=GID` where GID is the ID of the selected GPU (the first column in the `gpustat` or `nvidia-smi` listing).



= Running jupyter notebook on Apollo (Linux) =

This is a tutorial on how to run a Jupyter interface on apollo server.

== Connecting to apollo server ==
==== Connecting to FI MUNI VPN ====
- Download VPN configuration for FI MUNI here: https://www.fi.muni.cz/tech/unix/vpn.html.cs
- As login use facilty credentials (xsurname and secondary password)
==== Connecting to server ====
* Run command:
{{{
ssh xsurname@apollo.fi.muni.cz
}}}
* Type in secondary password

== Run Jupyter notebook with virtual env ==
==== Create virtual env and run it ====
{{{
virtualenv myenv
source myenv/bin/activate
}}}
==== Connect your virtual env with the Jupyter notebook ====
{{{
pip install ipykernel
python -m ipykernel install --user --name=myenv
}}}
You should get the output:
{{{
Installed kernelspec myenv in /home/user/.local/share/jupyter/kernels/myenv
}}}
* To check all your connected venvs
{{{
jupyter kernelspec list
}}}

==== Run Jupyter notebook on a personally selected port ====
{{{
jupyter notebook --no-browser --port 2222
}}}
==== Create SSH Tunnelling ====
* Open new second terminal and insert the following command
{{{
ssh xsurname@apollo.fi.muni.cz -NL 2222:localhost:2222
}}}
The second port must match the port selected when starting the jupyter notebook

==== Open Jupyter notebook on local machine ====
* Type in browser:
{{{
localhost:2222
}}}
Again this port must match the first port in ssh tunelling step
* Log  into the Jupyter notebook
* To get the token type:
{{{
jupyter notebook list
}}}
* Copy the token part and either create a password or log in with the token itself

== Change the cache location of !HuggingFace Datasets ==
* You need to change the download location of datasets. The default location is in your home and it can easly get full
* To change to Dataset location type:
{{{
export HF_DATASETS_CACHE="/path/to/another/directory"
}}}
* To make this change permanent so you don't need to type it every time you enter apollo add it to your .bashrc file at your home directory


== References used ==
1. SSH tunell: https://medium.com/@apbetahouse45/how-to-run-jupyter-notebooks-on-remote-server-part-1-ssh-a2be0232c533
2. FI MUNI VPN: https://www.fi.muni.cz/tech/unix/vpn.html.cs
3. Jupyter notebook with virtualenv: https://janakiev.com/blog/jupyter-virtual-envs/
4. !HuggingFace dataset location change: https://huggingface.co/docs/datasets/v1.12.0/cache.html