Wiss. Rechnen » Access
 

In order to obtain access to the cluster you need to do two things: firstly, you need to register your account for cluster usage and secondly you need to set up a Secure Shell (ssh) connection. On this page the first part is described, details about SSH connections can be found here.

You log in on the cluster with your ZIMT user ID and password, provided cluster usage is enabled for your ID as described below. You can also change the password of your ZIMT ID via the cluster.

Obtaining access: employees

University employees can request cluster access themselves. To do that you need to do the following:

  1. Log in to the Nutzerkontenverwaltung with your ZIMT ID
  2. Click on “Meine Konten/Dienste”.
  3. Next to your account name click on “Dienste beantragen”.
  4. Click the plus sign next to “High Performance Computing (HPC) – Linux cluster (HoRUS)”.
  5. Click “Bestellung einleiten” at the bottom of the page.
  6. Follow the instructions written in red.

Your application will normally be processed within a few days. You will receive an email “Welcome to the Cluster” which will give further details.

Obtaining access: students

Students can only use the cluster if they are assigned a supervisor who has to be an employee that already has cluster access. HPC access for students has a limited duration, but the duration can be extended each semester.

Adding a student as a supervisor

As a supervisor, you can add access for your students yourself. You only need the student’s ZIMT user ID.

To add a student, you need to do the following:

  1. Log onto the cluster using your own account.
  2. Initialize Kerberos by entering the following command:
    $ kinit

    You will be asked to enter your password.

    Note: the password will not be shown in the command line as you enter it, not even as stars.
  3. Load the studentadmin module on the cluster:
    $ module load studentadmin
    You will see a list of the available the studentadmin scripts:
    hpc_user_add.sh     .... adds user to group 
    hpc_user_prolong.sh .... prolongs user in a group 
    hpc_user_remove.sh  .... removes user from group 
    hpc_user_list.sh    .... lists users in group
    All scripts have a help function which you can display with the option -h. By default, the scripts will run in GUI mode and a window will open. Alternatively, you can run a script in batch mode with the option -b, for example when you want to add multiple students more quickly.
  4. To add an individual student, call the script hpc_user_add.sh. The following menu will appear:

    Usually, you will use the default mode. The expert mode allows you to assign students to specific user groups, this is only necessary in exceptional cases (see Linux basics). Using the default mode, students are assigned to the hpc-student group.
  5. Next, the following screen will appear, in which you can enter the ZIMT user ID of the person you would like to add:

    Again you can conform with Enter.
  6. You are then given the opportunity to verify the student’s user ID

    If you would like to correct the ID, use the arrow keys to change to “Nein” and conform with Enter. You will be prompted to enter the ID once more.
  7. When the user ID is found, you will receive the following message:

    Confirm with Enter again and the script will close.

The account will technically have access immediately, but the home directory will only be created the next day and the student will not be able to do much before then.

Student accounts will have access for 365 days until they need to be extended.

If you get an error message about missing permissions while registering your student, you need to log into the Nutzerkontenverwaltung once, this will update your account to work with the Nutzerkontenverwaltung.

A list of students can be added via batch mode. (User IDs are separated by whitespace.)
hpc_user_add.sh -b -u <user1> <user2> ...

Display remaining term with hpc_user_list.sh

Use hpc_user_list.sh to display all your students and their remaining term (in days). Select the GUI mode and enter the default group hpc-student or your specific user group. You can navigate through the list with the keys “Page-Up” and “Page-Down”. Exit the script with the enter key.

Extending student access as a supervisor

By default all students will be added for 365 days. Shortly before the time is up, the student will receive a warning via email. In that case you can extend their access with the hpc_user_prolong.sh script, its navigation works analogously to hpc_user_add.sh. You can show the remaining duration with hpc_user_list.sh. Remember to run kinit before using the studentadmin scripts.

Changing your password

You can change your password in Linux with the command passwd.

If you enter passwd, you will first be asked for your current password. Once this has been entered correctly, you can enter the new password. You will then have to type it a second time to confirm it.

Caution: If you change your password on the cluster, the change will apply to all other services linked to this user account as well (e.g. Moodle, Webmail, eduroam, …). The password can also be changed using this link.

Output of passwd:

$ passwd 
Ändern Passwort für Benutzer <user>. 
Aktuelles Passwort: 
Geben Sie ein neues Passwort ein: 
Geben Sie das neue Passwort erneut ein: 
passwd: alle Authentifizierungs-Merkmale erfolgreich aktualisiert.

Note: The password will not be shown in the command line as you enter it, not even as stars.

Aktualisiert um 17:42 am 12. August 2018 von Jan Philipp Stephan