How to Reverse Proxy Jupyter Notebook on a Subpath Using Nginx

Recently, I needed to proxy my Jupyter Notebook web interface from host.domain:8888 to a subpath directly from the HTTP 80 port host.domain/jupyter/. Unfortunately, the fact that Jupyter uses WebSocket for the communication between its kernel and the web application, makes setting up correct proxy in Nginx slightly more complicated. After a few searches and experimentation, I have reached a working solution, which I am documenting below.

In jupyter_notebook_config.py file

In order for the Jupyter server to serve files correctly, we need to set its base URL in $HOME/.jupyter/jupyter_notebook_config.py. Simply set or add the following line

c.ServerApp.base_url = '/jupyter/'

In http section of nginx.conf file

We need to create a variable based on the $http_upgrade value

map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}

In server section of nginx.conf file

We need to define a subpath and use the variable we just defined

location /jupyter/ {
        proxy_pass http://localhost:8888;
        proxy_http_version 1.1;
        proxy_set_header Host $http_host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
	proxy_set_header Connection $connection_upgrade;
	proxy_set_header Upgrade $http_upgrade;
}