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Issues can arise involving JupyterHub server (or less commonly, command-line Python). These browser and disk quota issues are similar to those seen for R, so see Troubleshooting R/RStudio server issues. If all else fails, submit a help request to our rctf-support@utexas.edu support email.
"Try restarting it from the hub" message
One issue specific to JupyterHub is getting 503: service unavailable. with the message: try restarting it from the hub after logging in with BRCF credentials. Sometime just clicking on the Restart button will work; if not, try logging in again.
JupyterHub Terminal issues
While JupyterHub's Terminal window is a great way to access the Linux command line from your web browser, there are some limitations you should be aware of:
- Some keystrokes and key combinations are not recognized the same way as on the real command line.
- This is especially true for Ctrl-, Function-, Option- Alt- key combinations.
- So, for example, editing a file with nano (or vi/vim or emacs) in the JupyterHub Terminal will not work when you try to enter an editor command.
- Be very careful looking at large files in the JupyterHub Terminal, since you may not be able to stop output of long test.
- Always pipe data from large files to a pager (e.g. more).
Problems arising from these limitations are the main cause of "Zombie" JupyterHub processes, described below.
Zombie processes
If you are unable to login to JupyterHub on one compute server, first try other compute servers on your pod if available.
Being blocked from logging in to JupyterHub on a compute server can be due to "zombie" JupyterHub processes that are still in a "running but not running" state. This is particularly common after using JupyterHub's Terminal window, especially if an error was encountered.
To you can find and kill any of your "Zombie" JupyterHub processes like this, after logging in to a specific compute server:
| Code Block |
|---|
# Find JupyterHub processes associated with <your_account>
ps -ef | grep jupyter
# The 2nd column in the listing, after your user name, is the process ID (PID).
# You can kill a process like this:
kill -9 <PID> |