A new software framework is presented for fast optimal designs of micromagnetic devices. The developed framework adopts a fast micromagnetic (FastMag) simulator as a micromagnetic solver, and utilizes distributed evolutionary algorithm in Python (DEAP). The framework makes use of a simple Linux utility for resource management (SLURM) in order to run and manage multiple micromagnetic simulations concurrently on a Linux cluster. Various design variables can be designated including material and geometry parameters. The whole design cycle is automated including the mesh generation, and the status of the evolution and multiple simulations can be monitored and managed easily. By combining high computing speed of FastMag and distributed optimization capability of DEAP and SLURM, the optimal designs of micromagnetic devices can be performed rapidly and efficiently. As numerical examples, the optimal designs of a spin-torque oscillator and a magnetic random access memory device are performed.