I'm afraid you've got dragons / Peter S. Beagle.

Dragons are common in the back-water kingdom of Bellemontagne, coming in sizes from mouse-like vermin all the way up to castle-smashing monsters. There are so many of them, the romance is long gone. They're pests, infestations, nuisances. Gaius Aurelius Constantine Heliogabalus Thrax (who would much rather people just call him Robert) has recently inherited his deceased father's job as a dragon catcher/exterminator, a career he detests with all his heart in part because he likes dragons, feeling an odd kinship with them, but mainly because his dream has always been the impossible one of transcending his humble origin to someday become a prince's valet. Needless to say, fate has something rather different in mind.