How to "undrain" slurm nodes in drain state

Found an approach, enter scontrol interpreter (in command line type scontrol) and then

scontrol: update NodeName=node10 State=DOWN Reason="undraining"
scontrol: update NodeName=node10 State=RESUME

Then

scontrol: show node node10

displays amongst other info

State=IDLE

Update: some of these nodes got DRAIN state back; noticed their root partition was full after e.g. show node a10 which showed Reason=SlurmdSpoolDir is full, thus in Ubuntu sudo apt-get clean to remove /var/cache/apt contents and also gzipped some /var/log files.

If no jobs are currently running on the node:

scontrol update nodename=node10 state=idle

If jobs are running on the node:

scontrol update nodename=node10 state=resume