Accessing the clusters

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Revision as of 07:41, 3 August 2016 by Sfux (talk | contribs) (Indirect GLX rendering error)

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In order to connect to one of the HPC clusters operated and maintained by ID SIS HPC, users need a valid NETHZ account. The clusters are open to all members of ETH and can even be used by external users that have a collaboration with a research group/institute at ETH Zurich.

ETH members

Members of ETH have immediate access to the clusters and can login with their NETHZ credentials.

External collaborators

Members of other institutes who have a collaboration with a research group at ETH may use the HPC clusters for the purpose of said collaboration. Their counterpart ("sponsor") at ETH must ask the local IT support group (ISG) of the corresponding department to create a NETHZ guest account for them, including e-mail address and VPN service.

First login

On the first login, users need to accept the cluster's usage rules. Afterwards their account is created automatically. A user account on a HPC cluster includes a home directory.


Users connect to the HPC clusters via the SSH protocol. For this purpose they need to have an SSH client installed.

Linux, Mac OS X




Mac OS X




Permission denied

If you enter 3 times a wrong password, then you will get a permission denied error:

samfux@bullvalene:~$ ssh's password: 
Permission denied, please try again.'s password: 
Permission denied, please try again.'s password: 
Permission denied (publickey,password,hostbased).

In case you receive a "Permission denied" error, please check if you entered the correct password. If you think that your account has been corrupted, then please contact the service desk of IT services of ETH Zurich.

If you enter a wrong password too many times or in a high frequency, then we might block access to the clusters for your account, because it could be correupted. If you account has been blocked by the HPC group, then please contact cluster support.


If you try to login and receive a timeout error, then it is very likely that you tried to connect from outside of the ETH network to one of the HPC clusters. Please either connect from the inside of the ETH network, or establish a VPN connection.

Indirect GLX rendering error

If you establish a SSH connection with X11 forwarding enabled and receive the following, when you start the graphical user interface of an application

X Error of failed request: BadValue (integer parameter out of range for operation)
  Major opcode of failed request: 153 (GLX)
  Minor opcode of failed request: 3 (X_GLXCreateContext)
  Value in failed request: 0x0
  Serial number of failed request: 27
  Current serial number in output stream: 30

then this means that you have started your X11 server without enabling the setting for indirect GLX rendering (iglx), that is required for X11 forwarding. Up to version 1.16 of the Xorg server, the setting iglx, has been enabled by default. With version 1.17, the default has changed from +iglx to -iglx. Now the setting needs to be enabled either in the Xorg configuration file or with a command line setting, when starting the Xorg server manually.

This problem is described in the following article:

For Xquartz versions up to 2.7.8, the iglx setting is enabled by default. If you would like to use XQuartz 2.7.9 or newer, then please make sure that you enable the iglx setting when the X-server is started.

External links

Operating system Link
Red Hat Enterprise Linux (RHEL)
Mac OS X