This document proposes a double resource renting scheme for cloud service providers to maximize profit while guaranteeing quality of service. It models the cloud system as an M/M/m+D queuing model. The scheme combines long-term and short-term server rentals to provide the necessary computing capacity over time. An optimization problem is formulated to determine the optimal server configuration that maximizes profit by balancing rental costs against increased revenue from meeting quality guarantees. Comparisons show the double renting scheme achieves higher profit than single renting while guaranteeing all requests are served on time.