Access: Terminal Interface#
We provide multiple methods to access the VSC clusters and use their computational resources. Not all options may be equally supported across all clusters though. In case of doubt, please contact the corresponding support team.
Secure Shell Connection#
You can open a terminal with a command prompt on any VSC cluster by logging in via the Secure Shell (SSH) protocol to the corresponding login node of that cluster. To this end, you will need to install and configure some SSH client software in your computer.
SSH client setup
SSH client setup
SSH client setup
Note
KU Leuven Logging in to a KU Leuven cluster with SSH requires Multi Factor Authentication.
Linux System#
All VSC clusters run the Linux kernel and a GNU operating system, so-called GNU/Linux or often just referred as Linux. Specifically, all our HPC clusters currently run some flavor of Red Hat Enterprise Linux, which means that all clusters share a common toolbox that can be used across VSC sites.
Once you connect to the terminal interface of a VSC cluster, you will be presented by a command line prompt that accepts Linux commands. It is hence necessary to have some knowledge on how to use the terminal in Linux to be able to perform any task in the system. The terminal might look daunting at first, as you have to known what commands to type to carry out even the simplest operations, like making folders and moving files. But making the effort to master the terminal is a guaranteed good investment of your time, as it is a very powerful tool that allows to extensively automate your workflows.
The following sections provide an introduction to the Linux terminal.
Graphical applications on the terminal#
Important
Recommended The Access: Web Portal provides a much better solution to run graphical applications on VSC clusters. Performance is faster and it is also easier to use. Consider running your graphical apps on it if available.
Launching programs with a graphical user interface (GUI) through the terminal interface of the cluster requires additional support on your SSH client. You need some software component that can encrypt and transfer through the network the graphical data of your application running on the cluster and display it on your screen.
X Server#
Most SSH clients provide integration with a so called X Server. This is a client/server solution that uses the X Window System protocol to display graphics on local or remote screens.
Displaying graphical applications running on the Linux system of the VSC cluster on your Windows system can be done by setting up an X Server on your computer:
Recommended MobaXterm provides an X Server, enable X11-Forwarding on your SSH connections to use graphical applications with it.
PuTTY provides an X Server, enable X11-Forwarding to use graphical applications on all your SSH connections.
Install a standalone X server such as Xming.
You can display remote graphical applications on your Mac with an X server. The recommended options is XQuartz which is an X Window System implementation freely available and supported by Apple.
Once XQuartz is installed and running on your Mac, you can simply open a terminal window and connect to a VSC cluster with SSH enabling support for graphics.
The X server is available on all popular Linux distributions, and most
often installed by default as well. You just need to use the appropriate
options with the ssh command to connect with support for
graphics.
Remote Desktop Environment#
You can launch a full-fledge remote desktop environment running on a remote VSC cluster with the VNC system. This solution generates a video stream of the remote graphical display, encrypts it and sends it over the SSH connection to your computer for visualization.
In this case all graphical processing occurs on the remove VSC cluster and your computer is only used for visualization and input. This can be useful in scenarios where you need heavy processing of graphics with the GPUs of the cluster.
Different options exist that provide a VNC-like solution. The available options depend on the operating system in your computer and the VSC cluster that you want to use:
On the KUL clusters, users can use NX NX Start Guide.
On the UAntwerp clusters, TurboVNC is supported on all regular login nodes (without OpenGL support) and on the visualization node of Leibniz (with OpenGL support through VirtualGL).
See the page Remote visualization @ UAntwerp for instructions.
VNC is supported through the Web portal interface.
On the VUB clusters, TigerVNC is supported on all nodes. See the documentation on remote desktop sharing for instructions.
Applications supporting SSH#
Some graphical applications provide their own functionality to run on remote servers through SSH. This can be used to run the GUI of such applications locally while the heavy lifting of the computation is done on a VSC cluster.
VPN#
Some institutes may have security policies forbidding the access to login nodes of your institute’s cluster from outside of the institute’s network (e.g. when you work from home) or from abroad. In such case, you will need to set up a VPN (Virtual Private Networking) connection to your institute’s network (if your institute provides this service) to be able to login to those VSC clusters.