start:mogon_cluster:access

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Essentially only accounts of the Johannes Gutenberg University can get access.

  • External users can approach us to retrieve more information concerning so-called guest accounts.
  • Internal groups with external members should approach their person in charge of accounts at the deanery of your faculty or at the secretariat of the respective institution.

Since the MOGON clusters are Linux-based systems, remote access is granted via SSH.

The MOGON login nodes are accessible only from the university network. To access MOGON from the outside (e.g. from home) you have to use VPN - please refer to these instructions:
(Outside) access using Unix / (Outside) access using Windows. The latter link also contains information for internal access with Windows.

Login to the login-nodes is mediated by a jump node: Access is done with direct login (ssh) to “mogon”. This name implements a 'Round-Robin-DNS' login to both login nodes of MOGON I, mil01.zdv.uni-mainz.de and mil02.zdv.uni-mainz.de. If for some reason you want to login to a specific login node, you can use this names directly. (or if for some other Reason one of the nodes is broken, and the dns always gives you the wrong, broken one to connect to)

The login nodes of MOGON II are miil01.zdv.uni-mainz.de to miil03.zdv.uni-mainz.de. Projects on MOGON I do not have access to MOGON II automatically. You have to apply for MOGON I and MOGON II separately. Only password-less login is available. You need to have your ssh-key1) on MOGON I to be able to log in to MOGON II.

The accelerators (GPUs) of MOGON II reside within MOGON I infrastructure that is to say you have to login to MOGON I but use your MOGON II account (-A m2_*) to have access to those accelerators.

You need to have your ssh-key on MOGON I to be able to log in to MOGON II. (RSA authentication)!

Your home directory is on the same file system on both clusters. In order to access MOGON II, you need to copy your ssh-key once to your home directory on MOGON I (~/.ssh).

SSH-Keys for MOGON require certain information in the comment of the SSH-Key that describes the purpose of the Key. The information is catched by a script and ensures that you can access MOGON correctly.

MOGON SSH-Key comment additions

Make sure you add the following strings to your SSH-Key after your actual comment, to specify the prupose:
Purpose MOGON String
Using the jump host hpcgate HPCGATE
Log in to MOGON service nodes HPCLOGIN

In case you not yet have an SSH-Key pair on your computer, you can use the following command to create a new pair:

ssh-keygen -t rsa -b 4096 -a 100 -C <YourComment>,<MOGON-String>

This generates a new private/public RSA key pair with 4096 bits. Then ssh-keygen asks for a name for the key (stay with the default if you don't have a good reason)

Enter a file in which to save the key (/home/you/.ssh/id_rsa): [Press enter] 

After that you have to specify a passphrase - Do not use an empty passphrase!

Enter passphrase (empty for no passphrase): [Type a passphrase]
Enter same passphrase again: [Type passphrase again] 
PuTTY must already be installed on your PC in order to follow these instructions.
  1. Ordered List ItemPress the -Key to open the start menu and type PuTTYgen, click on the App to open it. Now the PuTTY Key Generator window should be displayed..
  2. To create a new key pair, first select the type of the key to generate from the bottom. We recommend the RSA algorithm and 4096 bit key size.
  3. Now click on Generate and start moving the mouse within the Window, to let PuTTY collect some randomness for the Key.
    • Once the progress bar is full, the actual key generation takes place. Your public key should be appear in the windows once the compution is complete.
  4. Now you have to specify a Passphrase and add a Comment for your SSH-Key. Make sure you add the MOGON-String, to specify the purpose of your key.
  5. Click on the Save private key button to save your private key. You must save your private key.
  6. Now click on the Save public key button to save your public key.
  7. Right-click in the text field labeled Public key for pasting into OpenSSH authorized_keys file: and choose Select All/Alle auswählen.
  8. Right-click again in the same field and choose Copy/Kopieren.
  9. Browse to account.uni-mainz.de and add your new public SSH-Key. You will find further information in this Article.

1)
A neat overview on ssh-keys and how to generate and copy them can be found here.
  • start/mogon_cluster/access.1594816132.txt.gz
  • Last modified: 2020/07/15 14:28
  • by jrutte02