We presented the design of metallic-semiconductor nanolasers based on ring configuration lasing at around 1450 nm wavelength. The design and simulation of the nanolaser are done with 3D body-of-revolution (BOR) finite-differencetime- domain (FDTD) simulator based on a multi-level multi-electron system. Both passive cavity optimization and active laser simulation are carried out. New results are reported, but to be more comprehensive we also review some of our previous results. For the smallest design, which corresponds to one resonance order in the cavity, the total footprint of the nanolaser is only about 0.038 μm2, and the physical device volume and the mode volume are only about 1.1(λ/2n)3 and 0.001(λ/2n)3, respectively, where n is the average index of the gain material. This device by us is the smallest reported to date, to the best of our knowledge. We also design for higher resonance orders that have larger dimensions and better fabrication feasibility, as well as taking into consideration the fabrication tolerances. All these are presented in the paper.