Thanks for the quick answer ! That helps me going one step further.
It is a cluster I setup using kubeadm and 3 VM on a computer ( 1 master, 2 nodes). Just to play around before putting it in production.
Now the hub is failing with :
Not starting proxy
[W 2021-01-15 19:44:43.358 JupyterHub proxy:807] api_request to the proxy failed with status code 599
This post seems to be the same problem as me https://discourse.jupyter.org/t/proxy-error-599-when-i-try-to-make-an-offline-installation
But I am not sure to understand the solution given at the end.