You need a terminal and one of the three machines below. You do not need all three. The lesson pages link back here.
Snellius is the Dutch national supercomputer. SURF sends the account mail after your project has a login. The public description of the machine is at <https://www.surf.nl/en/services/compute/snellius-the-national-supercomputer>.
ssh YOUR_LOGIN@snellius.surf.nlSign in at <https://portal.cua.surf.nl/> before the first SSH login. If the network you are on is not trusted, the welcome mail names a door node. Use that host instead of snellius.surf.nl.
A browser session through Open OnDemand (<https://ondemand.snellius.surf.nl/>) is still a login node. Do not start the long run there.
The course cluster is a SURF Research Cloud workspace. CPU jobs request --partition=rome. The login address is the one in the welcome note. There is one login node. Your trainer sends a setup link. That link sets your password. There is no CUA account.
ssh YOUR_LOGIN@MANAGERmodule load 2025 loads EESSI 2025.06. module load 2024 selects that same stack. There is no project budget on this cluster. sacct still reports core-seconds in CPUTimeRAW.
mpiFileUtils is installed on this workspace. It is not an EESSI module. EESSI 2023.06 and 2025.06 do not provide it.
The software lesson also runs in the EESSI client container. Access is documented at <https://www.eessi.io/isc26-tutorial/getting-access/> and day-to-day use at <https://www.eessi.io/isc26-tutorial/usage/>.
You need Apptainer 1.0 or newer, with --fusemount support. This shell mounts the same repository the cluster uses. It does not give you Slurm.
mkdir -p "$HOME/eessi-work/var-lib-cvmfs" "$HOME/eessi-work/var-run-cvmfs" "$HOME/eessi-work/home"
export APPTAINER_BIND="$HOME/eessi-work/var-run-cvmfs:/var/run/cvmfs,$HOME/eessi-work/var-lib-cvmfs:/var/lib/cvmfs"
export APPTAINER_HOME="$HOME/eessi-work/home:/home/$USER"
apptainer shell --fusemount "container:cvmfs2 software.eessi.io /cvmfs/software.eessi.io" docker://ghcr.io/eessi/client:rocky8Inside the container:
source /cvmfs/software.eessi.io/versions/2025.06/init/lmod/bash
module load Python/3.13.5-GCCcore-14.3.0
python3 --versionpython3 --version prints Python 3.13.5. The first launch downloads the image and can take a few minutes. The container has no sbatch and no squeue.