https://stackoverflow.com/questions/68191801/why-are-my-slurm-job-steps-not-launching-in-parallel
#!/bin/bash #SBATCH --ntasks=2 srun --ntasks=1 sleep 10 & srun --ntasks=1 sleep 12 & wait
srun: Job 247 step creation temporarily disabled, retrying (Requested nodes are busy) srun: Step created for job 247
Depending on the Slurm version you might have to add the --exclusive parameter to srun (which has different semantics than for sbatch):
#!/bin/bash #SBATCH --ntasks=2 srun --ntasks=1 --exclusive -c 1 sleep 10 & srun --ntasks=1 --exclusive -c 1 sleep 12 & wait
https://stackoverflow.com/questions/50634447/multiple-tasks-in-the-same-node-with-slurm
https://stackoverflow.com/questions/35498763/parallel-but-different-slurm-srun-job-step-invocations-not-working