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Accessing MOGON

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, and 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 to 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.

MOGON Service Nodes Overiew

Service Node FQDN Cluster Service Node
login21 MOGON II Login Node
login22 MOGON II Login Node
login23 MOGON II Login Node
login01 MOGON I Login Node
login02 MOGON I Login Node
hpcgate MOGON Jump Host


You need to have your SSH-Key uploaded on to be able to log in to MOGON.

Your SSH-Key is automatically added to the MOGON clusters. Would You Like To Know More? Read this Article!

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 as part of your comment, to specify the purpose:
Purpose Comment String related to MOGON Access
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 [<Your Optional Comment>,]<gate-strings>

This generates a new private/public RSA key pair with 4096 bit key size. Then ssh-keygen asks for a name for the key.

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] 

If you already have an SSH-Key pair, you can change the comment as follows, for example to add a gate-string:

ssh-keygen -c -C "<YourNewComment>,<gate-string>" -f ~/Path/To/Your/PrivateKey
PuTTY must already be installed on your PC in order to follow these instructions.
  1. Press 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 HPCGATE,HPCLOGIN 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 and add your new public SSH-Key. You will find further information in this Article.

A neat overview on ssh-keys and how to generate and copy them can be found here. Or you can follow our guideline
  • start/mogon_cluster/access.1594848519.txt.gz
  • Last modified: 2020/07/15 23:28
  • by jrutte02