If a server is powered off, the wmf-reimage script will fail doing the power cycle with:

Set Chassis Power Control to Cycle failed: Command not supported in present state

The ipmipower (from freeipmi-tools) has an option --on-if-off that does exactly what we want.
Investigate if it's possible to do the same with ipmitool or change the ipmitool command on wmf-reimage to use ipmipower.