SSH ergonomics

A look at tools and practices that can help using SSH efficiently.

Objectives

  • Understand the universality/advantages of ssh keys

  • Create your own ssh key and register it

  • Adapt your ssh config to your needs for improved ergonomics

SSH keys

SSH key(pair)s are a mechanism for a remote machine to identify you.

It is a common authentication method when:

  • Connecting to HPC clusters

  • Authenticating to GitHub/GitLab

Generating a ssh keypair and registering it

A new key can be generated with the command

ssh-keygen -t ed25519

and following carefully the instructions that command tells you.

Warning

  1. Do not accidentally overwrite existing keys that can be in use.

  2. Do not use a passphrase-less ssh key

The procedure of creating a new key and register it needs to be repeated every 3 months.

The .ssh/config file

If we add the following text to the .ssh/config file:

Host uc3
    Hostname uc3.scc.kit.edu
    user <your-service-username>

we are allowed to connect BwUniCluster3.0 with the much simpler command

ssh uc3




- ssh keys: pros and cons
- Limitations specific to HoreKa and BWUniCluster
- `ssh-keygen`
- `ssh-agent`



## Security on HPC is important!

The May 2020 security outages:
- https://www.bwhpc.de/211.php
- https://www.bleepingcomputer.com/news/security/european-supercomputers-hacked-in-mysterious-cyberattacks/
- https://www.welivesecurity.com/2020/05/18/european-supercomputers-hacked-mine-cryptocurrency/