Issues influencing deployment

  • Early trials were showing memory problems in 16GB of RAM (app not loading properly) so 32GB RAM chosen
  • Voila not showing ipywidgets properly when deployed through apache2 so nginx chosen for easier proxying of web sockets
  • App was considered to be not mission critical so Amazon Spot Instance would be adequate giving 70% saving over Amazon On Demand Instance.
  • Deploy in Sydney data centre so most economic 32GB spot instance type available is t3.2xlarge (set max cost $0.20 per hour)
  • Choose latest LTS Ubuntu 20.04

Configure Ubuntu

After starting instance we get an IP address. We have a domain name for this instance tabulous.pythonator.com which we register with our DNS provider.

Now we can connect to the server using

ssh ubuntu@tabulous.pythonator.com

Install required packages

sudo apt install python3.8-venv mc nginx python3-certbot-nginx mongodb
  • Python venv to create python virtual environments
  • Midnight Commander mc for ease of file operations
  • Web server nginx for ease of web socket proxying
  • Let's encrypt certbot to create https certificate
  • Database mongodb to improve app load times rather than loading all data from csv to DataFrame every app load

Configure Voila/Jupyter

Create a directory called jupyter from which will run jupyter and voila. Install a python virtual environment so not to pollute system python.

mkdir -p jupyter/homesite-quote
cd jupyter
python3 -m venv venv
source venv/bin/activate

Configure python virtual environment for fastai, jupyter, ipywidgets, voila, kaggle and pymongo 

nano requirements.txt
    # jupyter/requirements.txt
    fastai==2.4.1
    fastbook==0.0.16
    fastcore==1.3.20
    fastprogress==1.0.0
    fastrelease==0.1.11
    ipykernel==5.5.5
    ipython==7.24.1
    ipython-genutils==0.2.0
    ipywidgets==7.6.3
    jupyter==1.0.0
    jupyter-client==6.1.12
    jupyter-console==6.4.0
    jupyter-core==4.7.1
    jupyter-server==1.10.1
    notebook==6.4.0
    numpy==1.20.3
    pandas==1.2.4
    scikit-learn==0.24.2
    scipy==1.6.3
    torch==1.8.1
    torchvision==0.9.1
    voila==0.2.10
    kaggle
    pymongo

pip install -r requirements.txt

Installing these python libraries will give an incompatibility with fastai requiring nbconvert<6 and voila requiring nbconvert>=6. Although not ideal, it seems we can ignore this for now.

Copy model to server from GPU computer 

scp learn_empty_dls_0708.pkl ubuntu@tabulous.pythonator.com:jupyter/homesite-quote/

Set up kaggle api 

mkdir ~/.kaggle
nano ~/.kaggle/kaggle.json
    {"username":"yourusername","key":"yourkey"}

Install app in jupyter folder 

cd ~/jupyter
git clone https://github.com/timcu/fast-tabulous-app.git

Configure Voila as a service and start 

sudo nano /etc/systemd/system/voila.service
    [Unit]
    Description=Voila
    [Service]
    Type=simple
    PIDFile=/run/voila.pid
    ExecStart=/home/ubuntu/jupyter/venv/bin/voila --no-browser --show_tracebacks=True fast-tabulous-app/fast-tabulous-with-db.ipynb
    User=ubuntu
    WorkingDirectory=/home/ubuntu/jupyter
    Restart=always
    RestartSec=10
    [Install]
    WantedBy=multi-user.target

sudo systemctl daemon-reload
sudo systemctl start voila  # start now
sudo systemctl enable voila  # start after every reboot or failure

Configure nginx 

sudo nano /etc/nginx/sites-available/tabulous.pythonator.com
    server {
        server_name tabulous.pythonator.com;
        root /var/www/tabulous.pythonator.com;
        proxy_buffering off;
        location / {
                proxy_pass http://localhost:8866;
                proxy_set_header Host $host;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

                proxy_http_version 1.1;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection "upgrade";
                proxy_read_timeout 86400;
        }
        client_max_body_size 100M;
        error_log /var/log/nginx/error.log;
        listen 80;
        listen [::]:80;
    }
cd /etc/nginx/sites-enabled
sudo ln -s ../sites-available/tabulous.pythonator.com

Now create a certificate for the site choosing redirect when asked the question

sudo certbot --nginx -d tabulous.pythonator.com  # 2 - redirect

It may be necessary to move all the proxy lines from 80 to 443 after reconfigured

Visit the site and check it all works

https://tabulous.pythonator.com

Troubleshooting jupyter

Connect to server tunnelling port 8888

ssh -L 8888:localhost:8888 ubuntu@tabulous.pythonator.com
cd jupyter
source venv/bin/activate
jupyter notebook

Then enter URL into browser on local computer. Running notebook should show log messages in console.

Troubleshooting voila

Connect to server tunnelling port 8866

ssh -L 8866:localhost:8866 ubuntu@tabulous.pythonator.com
cd jupyter
source venv/bin/activate
voila

Then enter URL into browser on local computer. Running notebook should show log messages in console.

Trougbleshooting voila service 

sudo systemctl status voila

Troubleshooting nginx

Check logs in /var/log/nginx