I will give as much detail as I can remember. I first read the book in 1980. I have searched sci-fi books back to the 1940's and still can't find this book. I believe it may either be a really old book, one that was renamed, or something that was dismissed as pulp sci-fi. The writing and story were pretty good, so I'm surprised I can't find it.
The book starts on Earth with a powerful ruling class that forms their own religion. The first high priest starts a dynasty and all subsequent rulers use his name followed by a roman numeral (like Egyptian Pharaohs or Popes). Before the end of his life, the first high priest has himself frozen so that he can be resurrected to a time when science can make him immortal. Subsequent rulers do the same, but the first high priest has deemed that their cryo units will kill them before they awake. There can be only one master.
This next part I may have confused with another book - All goes well until they discover that the Sun is going to expand and swallow the Earth. Maybe they just leave Earth for another reason, but they do leave in mass.
This part I do remember -They send out interplanetary probes and design spaceships. They finally find suitable planets and create several "Arks" (I think there were multiple, can't be sure). They put all the ruling class into cryo sleep, and crew the ships with "slaves" who are trained to maintain the equipment.
Aboard the ships, the crews live in a caste system where duties are passed down from father to son. It will take many generations before they arrive at the host planet, and the last generation will again be slaves of the sleeping masters. Something goes wrong and the ship's food system is destroyed. One of the slave mechanics investigates and finds the sleeping masters. He find ancient records and discovers the fate in store for them. The crew decides they will not be slaves again, and will save themselves by eating the frozen masters until they arrive at the planet.
The ship lands on the planet and they crew prepare a final ship's meal. The last cryo-chamber to be opened is very ornate and old. It is actually the first high priest froze many years ago. He is accidentally awakened because his cryo-chamber is automatically activated when opened. He expects that he will be worshiped and soon will watch "hot knives plunged into quivering pink flesh". He sees the common young girl who has opened his cryo-chamber and begins to shout orders at her. Before he can say anything, she cuts his throat and he is prepared for the first feast on the new planet.
