Q:

let slurmctld "think" that nodes are idle~ like after "SuspendProgram", but in fact they are down when it starts

Is  there a way to start slurmctld daemon with the execution nodes off, but making it to belive that he has requested the suspend for these nodes (e.g. like if it had called the SuspendProgram)? 
I am setting up a virtual cluster, so the SuspendProgram and ResumeProgram do terminate and instanciate virtual machines.  In this way I could power on only the master node, and he would fire up nodes only when requested.  
The problem is that for the moment, when I start slurmctld I need the nodes to get up, tell him that they exits, and wait that he shut them down.  This adds unwanted costs, because I need to poweron all the "supposed" instances. 
I would like to instanciate the master, the one running slurmctld, and let him think that the nodes are idle~ like after SuspendProgram. 
Cheers

A:

What you can try is set the nodes to state POWER_DOWN in slurm.conf so that at startup, slurmctld will see those nodes as powered down by SuspendProgram
NodeName=... Sockets=... CoresPerSocket... [etc] State=POWER_DOWN 

