You can inspect all environment variables available in a job by submitting the following jobscript
#!/bin/bash #SBATCH --nodes=1 --time=1:00 echo "-----" echo "Non-SLURM environment" echo "-----" env | grep -v SLURM echo "-----" echo "SLURM environment" echo "-----" env | grep SLURM
and inspecting the output.
SLURM sets automatically several environment variables. A non-exhaustive list of the most useful variables is shown here.
| Variable name | Description |
|---|---|
| USER | Your username. |
| HOSTNAME | Name of the computer currently running the script. |
| HOME | Your home directory. |
| PWD | Current directory the script is running in. Changes when you do cd in a script. |
| SLURM_SUBMIT_DIR | Directory where the sbatch command was executed. |
| SLURM_JOBID | ID number assigned to the job upon submission. The same number is seen in showq. |
| SLURM_JOB_NAME | Name of the job script. |
| SLURM_NODELIST | A collapsed list of nodes assigned to this job (see comments below) |
| SLURM_ARRAY_TASK_ID | Array ID numbers for jobs submitted with the -t flag. For #SBATCH -a 1-8, this will be an integer between 1 and 8. |
| SLURM_NTASKS | Number of tasks for the job. |
| SLURM_NTASKS_PER_NODE | Number of tasks per node. |
The list of nodes assigned to a job is stored in the variable $SLURM_NODELIST in a compact form (e.g: "tcn[1-10]" means nodes tcn1, tcn2, ..., tcn10 are assigned to the job). To obtain the full list of compute nodes available for the job you can use the following command:
scontrol show hostnames
which will print all the nodes available as ordered list, e.g:
tcn1 tcn2 tcn3 tcn4 tcn5 tcn6 tcn7 tcn8 tcn9 tcn10
On Snellius we are not exporting environment variables which are set by the user within the bash session.
This apply both to variables set by the user (interactively and in .bashrc or similar configuration files) or set by module files. This means that every variable you would like to be set at runtime, needs to be explicitly exported in the job script. Similar to this, any module you would like to have loaded at runtime, needs to be explicitly loaded within the job script.