If you want to set your Power machine to turn on automatically once it restarts or it is powered up, you can set the IPMI Power Restory Policy.
You can choose to keep the machine off, and you need to turn it on manually. You can also choose to power the machine on automatically. The other options involves keeping the previous state, i.e, keep the machine off if it was off before, and vice-versa.
In order to do it, you should use IPMI and point to the BMC, as in the following example, where I set the machine to power on automatically when it is plugged in the power outlet.
$ ipmitool -H <x.x.x.x> -I lanplus -U >PASSWORD> -P admin chassis power on