TLJH always serves /hub/ regardless of base_url parameter in config.yaml

[OffensiveGeneric]

Update by Erik - 2021-10-26

This was also reported in #655 with relevant logs.

Bug description

I am running a TLJH server on Ubuntu 20.04.3 LTS (Focal Fossa). I would like the login to be available at a path on a subdomain I own, some.domain.org/jupyter/hub (and eventually be able to serve a page at /jupyter that lists some other hubs). After searching for a while, I know that I should be able to do this with sudo tljh-config set base_url /jupyter and then sudo tljh-config reload proxy. Doing this makes sudo tljh-config show show correctly that the config.yaml file has been changed, but upon inspection, nothing in the traefik rules.toml has been updated (that is, the file still looks like)

[frontends.frontend__2F.routes.test]
rule = "PathPrefix:/"
data = "{\"hub\": true}"

What's going on here? Any workarounds?

Expected behaviour

sudo tljh-config set base_url /jupyter and then sudo tljh-config reload proxy should make the hub available on the path some.domain.org/jupyter/hub.

Actual behaviour

sudo tljh-config set base_url /jupyter and then sudo tljh-config show shows correctly that the config.yaml file has been changed, but upon inspection, nothing in the traefik rules.toml has been updated.

Your personal set up

• OS: Ubuntu 20.04.3 LTS (Focal Fossa)

• Full environment

the output of `pip freeze`
apturl==0.5.2
attrs==19.3.0
Automat==0.8.0
blinker==1.4
catfish==1.4.13
certifi==2019.11.28
chardet==3.0.4
Click==7.0
cloud-init==21.3
colorama==0.4.3
command-not-found==0.3
configobj==5.0.6
constantly==15.1.0
cryptography==2.8
cupshelpers==1.0
dbus-python==1.2.16
defer==1.0.6
distro==1.4.0
distro-info===0.23ubuntu1
entrypoints==0.3
httplib2==0.14.0
hyperlink==19.0.0
idna==2.8
importlib-metadata==1.5.0
incremental==16.10.1
Jinja2==2.10.1
jsonpatch==1.22
jsonpointer==2.0
jsonschema==3.2.0
keyring==18.0.1
language-selector==0.1
launchpadlib==1.10.13
lazr.restfulclient==0.14.2
lazr.uri==1.0.3
lightdm-gtk-greeter-settings==1.2.2
MarkupSafe==1.1.0
menulibre==2.2.1
more-itertools==4.2.0
mugshot==0.4.2
netifaces==0.10.4
oauthlib==3.1.0
olefile==0.46
onboard==1.4.1
pexpect==4.6.0
Pillow==7.0.0
psutil==5.5.1
pyasn1==0.4.2
pyasn1-modules==0.2.1
pycairo==1.16.2
pycups==1.9.73
PyGObject==3.36.0
PyHamcrest==1.9.0
PyJWT==1.7.1
pymacaroons==0.13.0
PyNaCl==1.3.0
pyOpenSSL==19.0.0
pyrsistent==0.15.5
pyserial==3.4
python-apt==2.0.0+ubuntu0.20.4.6
python-dateutil==2.7.3
python-debian===0.1.36ubuntu1
PyYAML==5.3.1
reportlab==3.5.34
requests==2.22.0
requests-unixsocket==0.2.0
SecretStorage==2.3.1
service-identity==18.1.0
sgt-launcher==0.2.5
simplejson==3.16.0
six==1.14.0
sos==4.1
ssh-import-id==5.10
systemd-python==234
Twisted==18.9.0
ubuntu-advantage-tools==27.2
ubuntu-drivers-common==0.0.0
ufw==0.36
unattended-upgrades==0.1
urllib3==1.25.8
wadllib==1.3.3
xcffib==0.8.1
xkit==0.0.0
zipp==1.0.0
zope.interface==4.7.1

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[consideRatio]

This seems like a straightforward bug associated with us not configuring traefik, but only c.JupyterHub.base_url, which isn't enough I presume.

[OffensiveGeneric]

This seems like a straightforward bug associated with us not configuring traefik, but only c.JupyterHub.base_url, which isn't enough I presume.

After hacking at it for a number of hours, I discovered that directly setting c.JupyterHub.base_url = '/jupyter' in the jupyterhub_config.py allows the base URL to persist between restarts of the hub & proxy services. The login becomes available on the desired URL path. However, it breaks the user environments and when a user logs in, they are unable to open any notebooks. I presume this has something to do with authentication/spawner aspects of the application. Either way, setting the config options in the config.yaml does nothing to affect the downstream variables. Going to try and figure this out today.

[consideRatio]

@OffensiveGeneric can you try verify if it breaks if a user logins - or if it breaks if a user tries to access their server? For me to follow clearly I may need to have a more clear description on "it breaks".

If you are testing things, test against:

• /jupyter/hub/home --- traefik proxy should take you to the hub
• /jupyter/user/username --- traefik proxy should take you to the user's server

[OffensiveGeneric]

@consideRatio

I am able to login to my account, and the login page is accessable from the correct URL. However a few times when I would login, the application would hang on the spawing page, being seemingly unable to spawn my environment. For whatever reason I'm having trouble reproducing this right now. UPDATE: here's an image of the spawing page hang, I was able to reproduce it.

Either way, afterwords, I am able to access my server from /home, but trying to make a new python notebook while in my server gives me this error. In fact, I cannot generate or upload any files at all.

I have a user account, tyler, in the hub which has admin privileges.

• /jupyter/hub/home --- traefik proxy should take you to the hub

This works as expected, I think. Once you are logged in, brings me here.

• /jupyter/user/username --- traefik proxy should take you to the user's server

This also works as expected, however for my account it adds /tree or in one instance /tree?#notebooks to the end of this url.

[mskblackbelt]

Is there any progress on this? If I could get TLJH running on a separate base_url, I might be able to make some progress on getting WebMO running on the same server. An alternative might be configuring jupyter-server-proxy, but I haven't had time to see if that will fit my requirements (or if it's even capable of doing the task I need).

I admit I'm unable to do much on my own, as I often don't know what it is I don't know… I'm trying to pick up things as fast as I can, but I run into missing vocabulary issues.

[OffensiveGeneric]

@consideRatio @mskblackbelt

For those curious, this should be considered fixed by the merge of Add base_url capability to tljh-config #623. If your install is from before this merge (Nov. 5, 2020), the feature to change the base url is broken/not configured properly.