Uller Uprising by H. Beam Piper [Federation Series #1]

In the distant future, humanity has colonized Uller, an Earthlike world twenty light-years from home. But Uller is already inhabited by a more primitive race, which soon comes under the control of Earth colonists reminiscent of the colonization of India in the 18th and 19th centuries. Like India, Uller will have its own Sepoy Mutiny...