Document some SSH tricks

[lesteve]

In my experience this is often one of the blocker because when you don't know them, it is super hard to find them by googling. It'd be good to have quick examples and point to some good reference doc for more details.

~/.ssh/config tricks with ProxyCommand

Generally you need two ProxyCommand (working from home going through your institute SSH gateway and then your authorised machine before reaching Jean Zay) but we chould start with one ProxyCommand (for example you are working from one machine that is not the authorised machine but can reach the authorised machine with ssh) to be easier to understand

Host institute-ssh-gateway
hostname ssh.gateway.your-institute.fr

Host your-authorised-machine
hostname your-authorised-machine.your-institute.fr
ProxyCommand ssh -W %h:%p institute-ssh-gateway

Host jean-zay
ProxyCommand ssh -W %h:%p your-authorised-machine
user your-jean-zay-login

Access IDRIS JupyterHub (https://jupyterhub.idris.fr) or extranet (https://extranet.idris.fr) if you are working from home

• SSH socks proxy

ssh -D 5000 -N your-authorised-machine

• change web browser proxy to use the socks proxy (on firefox it looks like this probably similar for other browsers)
  

Use fixed jean-zay machine so that you keep your tmux sessions.

Host jean-zay
# 3 login nodes: jean-zay1, jean-zay2, jean-zay3 at the time of writing: 2019-11-04
# better to keep it fixed for example for your tmux sessions to be on the same host
hostname jean-zay1.idris.fr
ProxyCommand ssh -W %h:%p your-authorised-machine
user your-jean-zay-login

and explain the trade-off that this particular login node can go down in which case you need to edit your ~/.ssh/config or add more aliases for the other login nodes.

sshfs in combination with Tensorboard running locally

already documented in https://jean-zay-doc.readthedocs.io/en/latest/tips-and-tricks/#run-sshfs-tensorboard-locally

[lesteve]

@rstrudel no pressure but if you had time to document how you use sshfs with Tensorboard running locally, I think this would be very helpful!

[lesteve]

Currently I am not sure I really understand the official Jean Zay suggestion (http://www.idris.fr/jean-zay/pre-post/jean-zay-jupyter-notebook.html#pour_tensorboard_sous_jupyter_notebook) but going through their less than optimal Jupyter wrapper (idrjup) to use Tensorboard is just not great (to put this nicely)

[guhur]

Here how I do to setup jeanzay with sshfs:

mkdir -p $PREFIX/scratch/jeanzay
sshfs -o reconnect,ServerAliveInterval=15,ServerAliveCountMax=3 jean-zay:/path/to/your/scratch/ $PREFIX/scratch/jeanzay