There is another alternative that is useful for diskful nodes running
an initramfs supplied by the distribution (which typically do not set a
hostname). If a node reaches rc.preinit without having a hostname set,
oneSIS can consult a list of MAC_ADDR directives and attempt to set the
hostname based on a mapping of one of its network interfaces. This is often
necessary for bringing up stand-alone nodes that don't use an initramfs
created by oneSIS.
Note: The MAC_ADDR directives are only used when no
hostname is set. They do not override a previously set hostname.