What does the installer do?

This document details what exactly the installer does to the machine it is run on.

apt Packages installed

The packages python3 and python3-venv are installed from the apt repositories. Since we need an recent & supported version of nodejs, we install it from nodesource.

Hub environment

JupyterHub is run from a python3 virtual environment located in /opt/tljh/hub. It uses the system’s installed python and is owned by root. It also contains a binary install of traefik. This virtual environment is completely managed by TLJH.

Note

If you try to remove TLJH, revert this action using:

sudo rm -rf /opt/tljh/hub

User environment

By default, a miniconda environment is installed in /opt/tljh/user. This contains the notebook interface used to launch all users, and the various packages available to all users. The environment is owned by the root user. JupyterHub admins may use to sudo -E conda install or sudo -E pip install packages into this environment.

This conda environment is added to $PATH for all users started with JupyterHub. If you are using ssh instead, you can activate this environment by running the following:

source /opt/tljh/user/bin/activate

This should let you run various conda and pip commands. If you run into errors like Command 'conda' not found, try prefixing your command with:

sudo PATH=${PATH} <command>

By default, sudo does not respect any custom environments you have activated. The PATH=${PATH} ‘fixes’ that.

Note

If you try to remove TLJH, revert this action using:

sudo rm -rf /opt/tljh/user

jupyterhub_config.d directory for custom configuration snippets

Any files in /opt/tljh/config/jupyterhub_config.d that end in .py and are a valid JupyterHub configuration will be loaded after any of the config options specified with tljh-config are loaded.

Note

If you try to remove TLJH, revert this action using:

sudo rm -rf /opt/tljh/config

Systemd Units

TLJH places 2 systemd units on your computer. They all start on system startup.

  1. jupyterhub.service - starts the JupyterHub service.

  2. traefik.service - starts traefik proxy that manages HTTPS

In addition, each running Jupyter user gets their own systemd unit of the name jupyter-<username>.

Note

If you try to remove TLJH, revert this action using:

# stop the services
systemctl stop jupyterhub.service
systemctl stop traefik.service
systemctl stop jupyter-<username>

# disable the services
systemctl disable jupyterhub.service
systemctl disable traefik.service
# run this command for all the Jupyter users
systemctl disable jupyter-<username>

# remove the systemd unit
rm /etc/systemd/system/jupyterhub.service
rm /etc/systemd/system/traefik.service

# reset the state of all units
systemctl daemon-reload
systemctl reset-failed

State files

TLJH places 3 jupyterhub.service and 4 traefik.service state files in /opt/tljh/state. These files save the state of JupyterHub and Traefik services and are meant to be used and modified solely by these services.

Note

If you try to remove TLJH, revert this action using:

sudo rm -rf /opt/tljh/state

User groups

TLJH creates two user groups when installed:

  1. jupyterhub-users contains all users managed by this JupyterHub

  2. jupyterhub-admins contains all users with admin rights managed by this JupyterHub.

When a new JupyterHub user logs in, a unix user is created for them. The unix user is always added to the jupyterhub-users group. If the user is an admin, they are added to the jupyterhub-admins group whenever they start / stop their notebook server.

If you uninstall TLJH, you should probably remove all user accounts associated with both these user groups, and then remove the groups themselves. You might have to archive or delete the home directories of these users under /home/.

Note

If you try to remove TLJH, in order to remove a user and its home directory, use:

sudo userdel -r <user>

Keep in mind that the files located in other parts of the file system will have to be searched for and deleted manually.

Note

To remove the user groups units:

sudo delgroup jupyterhub-users
sudo delgroup jupyterhub-admins
# remove jupyterhub-admins from the sudoers group
sudo rm /etc/sudoers.d/jupyterhub-admins

Passwordless sudo for JupyterHub admins

/etc/sudoers.d/jupyterhub-admins is created to provide passwordless sudo for all JupyterHub admins. We also set it up to inherit $PATH with sudo -E, to more easily call conda, pip, etc.

Removing TLJH

If trying to wipe out a fresh TLJH installation, follow the instructions on how to revert each specific modification the TLJH installer does to the system.

Note

If using a VM, the recommended way to remove TLJH is destroying the VM and start fresh.

Warning

Completely uninstalling TLJH after it has been used is a difficult task because it’s highly coupled to how the system changed after it has been used and modified by the users. Thus, we cannot provide instructions on how to proceed in this case.