Configure the Provisioning Server to Wake Targets
sudo apt-get install powerwake
Configure the Target Systems to Wake-On-Lan
Boot each target server to BIOS, and ensure that Wake-on-Lan (WoL) is enabled. Refer to your BIOS documentation, if necessary.
In some cases, you might have to additionally enable your ethernet card for WoL in Linux userspace as well. This command should do it:
sudo /usr/sbin/ethtool -s $i wol g
Or, you can just install powernap, which will do this on every boot.
sudo apt-get install powernap