I'm pretty certain that the North Koreans, at least those who have a say in it, want war. There's nothing worse than a totalitarian government that runs every aspect of the affairs of a well-armed, yet poor nation. They have a big army, they have nothing to lose, and societies like theirs would thrive off the pride generated from a national campaign.
They want to get into it with somebody. They're betting we don't have the resolve to hit them with any lasting effect. They're pretty certain that they'll get a few good licks in before things come to a stop. At this point, it's just a matter of provoking the other guy into starting it, thus legitimizing their righteousness.