SSH keys on new HAL DGX setup

[matthewfeickert]

Continuing the thread of thought from Issue #14, the login machine also makes it difficult to do ssh-key forwarding. While there is a default ssh-agent running on the login machine, there is no default agent running on HAL DGX itself now. This poses a problem as it makes ssh-key forwarding impossible even with a profile like

Host DGX HALDGX
    HostName hal-login3.ncsa.illinois.edu
    Compression yes
    PreferredAuthentications keyboard-interactive,password
    PubkeyAuthentication no
    ForwardAgent yes
    User feickert

and users should ideally not be trying to automate setting up a ssh-agent on login. So this will need to get figured out.

---

Example:

$ ssh DGX
feickert@hal-login3.ncsa.illinois.edu's password: 
Duo two-factor login for feickert

Enter a passcode or select one of the following options:

 1. Duo Push to XXX-XXX-XXXX

Passcode or option (1-1): 1
Success. Logging you in...
Last login: Wed Apr 27 21:58:21 2022 from 216.169.6.123
 __          __  _                            _          _    _          _          _                 _       ____    _ 
 \ \        / / | |                          | |        | |  | |   /\   | |        | |               (_)     |___ \  | |
  \ \  /\  / /__| | ___ ___  _ __ ___   ___  | |_ ___   | |__| |  /  \  | |  ______| |     ___   __ _ _ _ __   __) | | |
   \ \/  \/ / _ \ |/ __/ _ \| '_ ` _ \ / _ \ | __/ _ \  |  __  | / /\ \ | | |______| |    / _ \ / _` | | '_ \ |__ <  | |
    \  /\  /  __/ | (_| (_) | | | | | |  __/ | || (_) | | |  | |/ ____ \| |____    | |___| (_) | (_| | | | | |___) | |_|
     \/  \/ \___|_|\___\___/|_| |_| |_|\___|  \__\___/  |_|  |_/_/    \_\______|   |______\___/ \__, |_|_| |_|____/  (_)
                                                                                                 __/ |                  
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[feickert@hal-login3 ~]$ srun --partition=x86 --time=1:00:00 --nodes=1 --ntasks-per-node=32 --sockets-per-node=1 --cores-per-socket=16 --threads-per-core=2 --mem-per-cpu=4000 --wait=0 --export=ALL --gres=gpu:a100:1 --pty /bin/bash
(base) [feickert@hal-dgx ~]$ ssh-add -l
Error connecting to agent: No such file or directory
(base) [feickert@hal-dgx ~]$ eval $(ssh-agent)
Agent pid 59269
(base) [feickert@hal-dgx ~]$ ssh-add -l
The agent has no identities.