start:mogon_cluster:access

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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.

#### Remote Access

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

To access MOGON refer to these instructions: access MOGON using Linux/macOS / access MOGON using Windows. The latter link contains information for accessing MOGON with PuTTY, MobaXterm and PowerShell.

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.

#### MOGON Service Nodes Overiew

Service Node FQDN Cluster Description
login21 miil01.zdv.uni-mainz.de MOGON II Login Node
login22 miil02.zdv.uni-mainz.de MOGON II Login Node
login23 miil03.zdv.uni-mainz.de MOGON II Login Node
hpcgate hpcgate.zdv.uni-mainz.de MOGON Jump Host

#### Service-Node FQDN

If you access MOGON Service-Nodes through the HPCGATE you can omit zdv.uni-mainz.de, e.g.: for login21 miil01 is sufficient.

#### SSH-Key

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.

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 -C "HPCGATE,HPCLOGIN"

This generates a new private/public RSA key pair with 4096 bit key size.
Please note: The part -C “HPCGATE,HPCLOGIN” creates the mandatory comment, which can be pasted into the web form.
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 - use a passphrase! . An empty passphrase is a serious security concern.

Enter passphrase (empty for no passphrase): [Type a passphrase]
Enter same passphrase again: [Type passphrase again] 

In this case you deviate from the default names and you ought make your ssh-agent aware of it:

ssh-add ~/Path/To/Your/PrivateKey

#### Modify existing SSH-Keys

If you already have an SSH-Key pair, you can change the comment as follows, for example to add the HPCGATE,HPCLOGIN string if you have forgotten to append it:

ssh-keygen -c -C "HPCGATE,HPCLOGIN" -f ~/Path/To/Your/PrivateKey

#### Set up SSH-Keys for MOGON using Windows

We have created an article for you that explains various ways to create new SSH-Keys using Windows, including PuTTY, MobaXterm and PowerShell.

1)
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.1601892458.txt.gz