Accessing Katana

If you have would like to request an account on Katana or wish to talk about any aspect of High Performance Computing then please send an email to

Once you have been given access to Katana you will be sent an email with detailed instructions and you will then be able to log on to the system using SSH using your zID and zPass.

Linux and Mac

From a Linux or Mac OS machine this can be done as follows:

desktop:~$ ssh


From a Windows machine a SSH client such as PuTTY is required. Once you have downloaded PuTTY you open it, make sure that SSH is selected and enter the host name of the cluster so that it looks like the image below.

You should also type "Katana" under "Saved Sessions" and click on save so that your connection settings are saved for next time. Now click on "Open" and you will get a security alert. Accept the security key and you will be asked for your username and password (zID and zPass).

SSH Issues

With all networks there is a limit to how long a connection between two computers will stay open if no data is travelling between them. This can cause problems when you are connected to Katana to run interactive jobs or even if you step away from your computer.


The solution to this problem is to set the SSH keepalive variable to 60 seconds as shown in the PuTTY configuration image below.

Linux / Mac

If you use a Linux or Mac computer then you can change the same setting by creating a file
~/.ssh/config which contains the following lines

Host *
  ServerAliveInterval 60

Keeping things running while you disconnect

In order to make sure that your commands will keep running even if you are disconnected you should use the 'screen' command. To start a new screen we use the command screen -S ID so we start a new screen by typing$ screen -S zID

and then you can run the commands that you usually do.

At any time you can detach the screen by typing Control a then Control d and log out. When you log back in you can check your progress by typing$ screen -R

to re-attach the screen.

When you are finished with the screen you can close it in the same manner that you would use to log out.

Copying files in and out

More information about file storage is available in the storage section of the web site but the easiest way to copy files and data to and from Katana is to use FileZilla ( which provides you a graphical way to copy files and even edit files in situ.

Graphical sessions

If you have connected from a Linux machine (or a Mac with X11 support via or XQuartz) then connecting via SSH will allow you to open graphical applications from the command line. To run these programs you should start an interactive job on one of the compute nodes so that none of the computational processing takes place on the head node.

If you require an interactive graphical session to Katana then you can use X2Go which is available from Download and install the version of the X2Go client that matches your operating system. Then start X2Go and create a session for Katana. The details that you need to enter for the session are:

  • Session name: Katana
  • Host:
  • Login: zID
  • Session type: Gnome

Once you have created the session you can then click on it to connect to Katana.

Note: If you use X2Go from a Mac then you may get the following errors:

  1. SSH daemon failed to open the application's public host key.
  2. Connection failed Cannot open file -

This happens because of missing SSH key files on the Mac client. To force the Mac to generate these keys log in over SSH from a Windows computer using PuTTY (or Linux computer using SSH) which will generate the missing SSH key files.

Note: The usability of a graphical connection to Katana is highly dependent on network latency and performance.