Known Issues on JUSUF

This page collects known issues affecting JUSUF’s system and application software.


The following list of known issue is intended to provide a quick reference for users experiencing problems on JUSUF. We strongly encourage all users to report the occurrence of problems, whether listed below or not, to the user support.

Open Issues

Job requeueing failures due to slurmctld prologue bug

Added: 2021-05-18

Affects: All systems at JSC

Description: There is a bug in slurmctld and currently the prologue mechanism and the job requeueing are broken. Normally before a job allocates any nodes the prologue runs and if it finds unhealthy nodes it drains them and requeues the job. Because of the bug now slurcmtld will cancel the jobs that were requeued at least once but finally landed on healthy nodes. We have reported this bug to SchedMD and they are working on it.

Status: Open.

Cannot connect using old OpenSSH clients

Added: 2020-06-15

Affects: All systems at JSC

Description: In response to the recent security incident, the SSH server on JUSUF has been configured to only use modern cryptography algorithms. As a side effect, it is no longer possible to connect to JUSUF using older SSH clients. For OpenSSH, at least version 6.7 released in 2014 is required. Some operating systems with very long term support ship with older versions, e.g. RHEL 6 ships with OpenSSH 5.3.

Status: Open.

Workaround/Suggested Action: Use a more recent SSH client with support for the newer cryptography algorithms. If you cannot update the OpenSSH client (e.g. because you are not the administrator of the system you are trying to connect from) you can install your own version of OpenSSH from Logging in from a different system with a newer SSH client is another option. If you have to transfer data from a system with an old SSH client to JUSUF (e.g. using scp) you may have to transfer the data to a third system with a newer SSH client first (scp’s command line option -3 can be used to automate this).

Recently Resolved and Closed Issues