External sources

The following external sources provide a great deal of information about HPCs. If you are new to HPCs, please use these sources (and other information on the web) to fill up the knowledge gaps:

Using the shell

To access and use AWI's HPC systems login via a terminal is needed, using ssh.

Although, in general it is possible to use tools with a graphical user interface (GUI) remotely via ssh, some basic knowledge on how to use the shell is required.

We advise all new users, who have never worked in a shell on a Unix-like system, to go through this nice introduction: 

https://swcarpentry.github.io/shell-novice/

This tutorial is a good starting point where you learn to navigate in the filesystem, manipulate files, and create and run scripts.

Login with ssh-keys

Resources

Example: Albedo

Here is an example for a user named "user" and a desktop named "desktop" connecting to NEC Albedo. Please replace username and remote machine accordingly!

  • Generate a key on your local desktop or whatever machine you want to connect to albedo0 and albedo1

    user@desktop:~$ ssh-keygen -t ed25519 -a 100 -f ~/.ssh/id_ed25519_albedo

    You are asked for a passphrase. A passphrase increases the security in case your account is hacked or your notebook gets lost, and it is a must for connections between systems at different locations, e.g., from AWI to HLRN or from home to AWI. Please use a strong passphrase to secure your key.
    Two files are generated

    1. the private key ~/.ssh/id_ed25519_albedo remains on your local machine,

    2. the public key ~/.ssh/id_ed25519_albedo.pub is copied to the remote machine.

  • Our recommendation is to have a pair of private+public keys for each local+remote connection. It helps to keep an overview and a good naming scheme helps to prevent the danger of overwriting an existing key.
  • Make sure you are connected to the AWI network (via ethernet or VPN)

  • Copy the public key to Albedo, here to albedo1, also makes the key available on albedo0, as they share the home directory:

    user@desktop:~$ ssh-copy-id -i ~/.ssh/id_ed25519_albedo.pub <your_username>@albedo1.dmawi.de

    For some destinations, to increase the security, the public key has to be uploaded in a web portal, and it is not placed in your remote home directory. For Albedo the command above is all you need.

  • Log in to albedo0 or albedo1 with

    user@desktop:~$ ssh -i ~/.ssh/id_ed25519_albedo -Y <your_username>@albedo0.dmawi.de

  • Or, for convenience, add an entry to ~/.ssh/config on your local desktop. Generate this file, if not yet present.

    user@desktop:~$ cat ~/.ssh/config
    Host albedo0
       Hostname albedo0.dmawi.de
       IdentityFile ~/.ssh/id_ed25519_albedo
       user <your_username>

    and log in with

    user@desktop:~$ ssh -Y albedo0

For more details about ssh have a look at SSH.