google auth breaks on debian because username fail badname check

[joequant]

Bug description

google auth creates usernames with @ in them but useradd in debian fails to create these usernames without a --badname flag

How to reproduce

Set up google auth on debian

Expected behaviour

Should create new user and jupyterhub environment

Actual behaviour

Breaks with error

Your personal set up

OS: Debian 13

Logs

Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]: [E 2026-04-04 09:16:11.207 JupyterHub user:1004] Unhandled error starting joequant@bitquant.com.hk's server: Command '['useradd', '--create-home', 'jupyter-joequant@bitquant.-1a662']' re>
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:     Traceback (most recent call last):
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       File "/opt/tljh/hub/lib/python3.13/site-packages/jupyterhub/user.py", line 914, in spawn
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:         f = maybe_future(spawner.start())
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:                          ~~~~~~~~~~~~~^^
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       File "/opt/tljh/hub/lib/python3.13/site-packages/tljh/user_creating_spawner.py", line 26, in start
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:         user.ensure_user(system_username)
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:         ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       File "/opt/tljh/hub/lib/python3.13/site-packages/tljh/user.py", line 29, in ensure_user
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:         subprocess.check_call(["useradd", "--create-home", username])
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:         ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       File "/usr/lib/python3.13/subprocess.py", line 419, in check_call
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:         raise CalledProcessError(retcode, cmd)
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:     subprocess.CalledProcessError: Command '['useradd', '--create-home', 'jupyter-joequant@bitquant.-1a662']' returned non-zero exit status 19.
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:     
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]: [E 2026-04-04 09:16:11.265 JupyterHub pages:364] Error starting server joequant@bitquant.com.hk: Command '['useradd', '--create-home', 'jupyter-joequant@bitquant.-1a662']' returned non-z>
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:     Traceback (most recent call last):
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:     NoneType: None
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:     
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]: [W 2026-04-04 09:16:11.266 JupyterHub web:1964] 500 GET /hub/spawn (::1): Unhandled error starting server joequant@bitquant.com.hk
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]: [E 2026-04-04 09:16:11.269 JupyterHub log:184] {
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Host": "compute.hkphysics.hk",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:151.0) Gecko/20100101 Firefox/151.0",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Accept-Encoding": "gzip, deflate, br, zstd",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Accept-Language": "en-US,en;q=0.9",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Cookie": "_xsrf=[secret]; jupyterhub-hub-login=[secret]; jupyterhub-session-id=[secret]",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Priority": "u=0, i",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Sec-Fetch-Dest": "document",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Sec-Fetch-Mode": "navigate",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Sec-Fetch-Site": "none",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Sec-Fetch-User": "?1",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Te": "trailers",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "Upgrade-Insecure-Requests": "1",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "X-Forwarded-For": "::1",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "X-Forwarded-Host": "compute.hkphysics.hk",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "X-Forwarded-Port": "80",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "X-Forwarded-Proto": "http",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "X-Forwarded-Server": "debian-s-2vcpu-2gb-sgp1-01",
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:       "X-Real-Ip": "::1"
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]:     }
Apr 04 09:16:11 debian-s-2vcpu-2gb-sgp1-01 python3[14586]: [E 2026-04-04 09:16:11.269 JupyterHub log:192] 500 GET /hub/spawn (joequant@bitquant.com.hk@::1) 161.08ms

[jrdnbradford]

@joequant, I was able replicate this error on a Debian 13 TLJH. You may be able to get around this if bitquant.com.hk is your only domain by adding the following to your Google OAuthenticator configuration:

c.GoogleOAuthenticator.hosted_domain = ['bitquant.com.hk']

and then reloading:

sudo tljh-config reload

This seems more like an OAuthenticator bug which can be filed at https://github.com/jupyterhub/oauthenticator/issues if the above doesn't help.

[jrdnbradford]

@joequant did this help?

[jrdnbradford]

Turns out there is already an issue filed in the oauthenticator repo with some workarounds: jupyterhub/oauthenticator#399