Interactive Sessions

The Elysium cluster provides the possibility to work interactively to allow compute intensive preparations, post processing steps, or tests. Further, interactive sessions on the visualization nodes (vis[001-003]) allow for remote connections to run e.g. jupyter notebooks from your local machine.

Interactive Jobs

In order to reserve nodes interactively the following command should be used:

[login_id@login001 ~]$ srun -N 1 --partition=vis --job-name=interactive --time=01:00:00 --tasks-per-node=1 --account=<project_name> --pty bash

Depending on the load on the cluster it might take some time until resources can be allocated for your job. Even if resources are free the scheduler might need a few seconds to reserve the requested node. If you require a specific node for your interactive session you may utilize the -w <nodename> flag. Note that this might increase the time for your session to start until the requested node is available.

(For more options on node allocations see SLURM).

SSH From Login Node to Interactive Session

As long as you have any job running on the target node you can use ssh to connect from any login node to your target node. When the job terminates, all ssh connections will be terminated as well.

SSH From Local Machine to Interactive Session

Connection to compute nodes from local machines is only possible for the three visualization nodes (vis[001-003]). In order to allow a local machine to connect to a node with an active job, one of the login nodes needs to be defined as a jump host, to forward your ssh request.

Please make sure that the ~/.ssh/config on your local machine contains the following entries:

Host elysium-login001
    User <login_id>
    Hostname login001.elysium.hpc.rub.de
    IdentityFile ~/.ssh/elysium

Host *.elysium.hpc.rub.de *.elysium.hpc.ruhr-uni-bochum.de !login*.elysium.hpc.rub.de !login*.elysium.hpc.ruhr-uni-bochum.de
    User <login_id>
    IdentityFile ~/.ssh/elysium
    ProxyJump elysium-login001

Please ensure that the IdentityFile points to the correct (private) key. You are now able to connect to connect to one of the vis nodes with the following command:

[localuser@localmachine ~]$ ssh vis001.elysium.hpc.rub.de
[<login_id>@vis001 ~]$