Hello, I think you could use SLURM's power saving mecanism to shut down all your nodes simultaneously. Then doing srun -N<nb_nodes> -C <your_node_group> true (or any other small work) will wake up N nodes simultaneously. You can even do srun while your nodes are powering down, SLURM will reboot them as soon as they're powered down.
I hope it will be helpful ! Regards, C.Mercier
